What is a sliding scale insulin chart?

A sliding scale (correction scale) chart lists blood sugar ranges and the number of units of rapid- or short-acting insulin to give for each range. You check your blood sugar, find the row, and give that dose — usually before meals and at bedtime. On the moderate-dose example chart here, 151–200 mg/dL is 2 units, 201–250 is 4 units and 251–300 is 6 units; below 70 mg/dL means no insulin and treat the low. Real charts are written by the prescriber for each patient.

What are the low, moderate and high dose sliding scales?

They are the same chart with different doses per row. In the examples on this page each 50 mg/dL above 150 adds 1 unit (low dose), 2 units (moderate) or 3 units (high dose), so 247 mg/dL gives 2 / 4 / 6 units. The ADA suggests matching the scale to the total daily insulin dose: a low scale under 40 units/day, medium for 40–80 and high above 80 units/day.

What is a low dose (mild) sliding scale insulin chart?

A low-dose scale is for people who are sensitive to insulin — small or older adults, people with kidney disease, those eating little, or anyone on under about 40 units a day. The example here gives 1 unit for 151–200 mg/dL, 2 for 201–250, 3 for 251–300, 4 for 301–350, 5 for 351–400 and 6 above 400 (call the prescriber). In mmol/L that is 1 unit at 8.4–11.1, 2 at 11.2–13.9 and 3 at 14.0–16.7.

What does a high dose (aggressive) sliding scale look like?

High-dose or insulin-resistant scales give larger steps for people needing over about 80 units a day, on steroids or with infection. The example gives 3 units at 151–200 mg/dL, 6 at 201–250, 9 at 251–300, 12 at 301–350, 15 at 351–400 and 18 above 400. The published RABBIT 2 "insulin resistant" column is similar: 6 units at 141–180 up to 18 units above 400 mg/dL.

How do you calculate a sliding scale insulin dose?

Read the dose from the row your blood sugar falls in. Behind most scales is a correction factor: dose = (blood sugar − target) ÷ correction factor. With a total daily dose of 40 units, the 1800 rule gives a factor of 45 mg/dL per unit, so 250 mg/dL with a 120 target needs (250 − 120) ÷ 45 = 2.89, about 3 units. Band charts round this into fixed steps so nurses and patients can read the dose at a glance.

What does "1 unit per 50 over 150" (1:50 > 150) mean?

It means 1 unit of insulin for every 50 mg/dL above 150: 151–200 = 1 unit, 201–250 = 2 units, 251–300 = 3 units, and so on. At 280 mg/dL that is 3 units. A 1:25 order is twice as strong — 1 unit per 25 mg/dL above 150 — giving 6 units at 280. Use the Custom option in the calculator to print any such scale.

On a lispro sliding scale, how many units do I need for a blood sugar of 247?

It depends on which scale is ordered. On the example charts, 247 mg/dL (13.7 mmol/L) is in the 201–250 row: 2 units on the low-dose scale, 4 on moderate and 6 on high. On the RABBIT 2 scale it is the 221–260 row: 6 / 8 / 10 units. Because 247 is above 240 mg/dL, also check ketones if you have type 1 diabetes or feel unwell.

How much insulin is given for a blood sugar of 450 (25 mmol/L)?

450 mg/dL (25 mmol/L) is in the top ">400" row of most scales — 6 / 12 / 18 units on the low, moderate and high examples and 14 / 16 / 18 on RABBIT 2 — and almost every order says to call the prescriber at this level. Check ketones. Vomiting, abdominal pain, fast breathing or confusion with a reading this high can mean diabetic ketoacidosis and need emergency care.

What is the sliding scale insulin chart in mmol/L?

Divide mg/dL by 18 to get mmol/L (multiply mmol/L by 18 to go back). The example scales in mmol/L: no correction up to 8.3; 8.4–11.1 → 1 / 2 / 3 units (low / moderate / high); 11.2–13.9 → 2 / 4 / 6; 14.0–16.7 → 3 / 6 / 9; 16.8–19.4 → 4 / 8 / 12; 19.5–22.2 → 5 / 10 / 15; above 22.2 → 6 / 12 / 18 and call. A reading of 10 mmol/L (180 mg/dL) gives 1 / 2 / 3 units.

How do I work out how many units of fast-acting insulin to take for my mmol/L reading (UK)?

UK teams usually use a correction factor from the "100 rule": 100 ÷ total daily dose = how many mmol/L one unit lowers your glucose. With 40 units a day, 1 unit lowers about 2.5 mmol/L, so a reading of 16 with a target of 6 needs (16 − 6) ÷ 2.5 = 4 units. Do not repeat a correction within about 2 hours. In UK hospitals, "sliding scale" usually means an IV insulin infusion, now called a variable rate intravenous insulin infusion (VRIII).

Which insulin is used for a sliding scale — regular or rapid-acting?

Either a rapid-acting analog (lispro/Humalog, aspart/NovoLog, glulisine/Apidra) or short-acting regular insulin (Humulin R, Novolin R, Actrapid). Rapid-acting insulin starts working within about 15 minutes, peaks at about 1 hour and lasts about 4 hours, so it is given just before eating. Regular insulin starts in about 30 minutes, peaks at 1.5–2 hours and lasts 4–6 hours, so it is given 30 minutes before a meal. The RABBIT 2 sliding-scale arm used regular insulin.

How often can sliding scale insulin be given?

If the person is eating: before each meal and often at bedtime (with a smaller bedtime scale). If not eating, or on continuous tube feeds: every 4–6 hours, per the ADA, with glucose checks at the same interval. Repeating rapid-acting corrections within about 2–3 hours "stacks" insulin and can cause a late low. Hourly checks with insulin every hour or two belong to IV insulin infusions, not subcutaneous scales.

At what blood sugar do you start sliding scale insulin?

The ADA says correction insulin typically starts at 140 or 150 mg/dL (7.8 or 8.3 mmol/L). In hospital, insulin is started or increased for persistent glucose of 180 mg/dL (10.0 mmol/L) or more on two readings within 24 hours, and the goal is 100–180 mg/dL for patients outside intensive care and 140–180 mg/dL in intensive care.

Is sliding scale insulin still recommended?

Not on its own. ADA Standards of Care 2026 discourage using correction insulin without basal insulin ("formerly referred to as a sliding scale") for most hospitalized people, and strongly discourage prolonged use, except for type 2 diabetes with mild or stress hyperglycemia that stays under 180 mg/dL. In the RABBIT 2 trial, 66% of patients on basal-bolus insulin reached a mean glucose under 140 mg/dL versus 38% on sliding scale alone. Correction scales are still used — on top of scheduled basal and mealtime insulin.

Is there a sliding scale for type 2 diabetes?

Yes — the same correction charts are used for type 2 diabetes, usually added to basal insulin or tablets. RABBIT 2 was done in hospitalized type 2 patients: those on sliding scale alone who stayed above 240 mg/dL were switched to basal-bolus insulin at 0.5 units/kg/day. At home, many people with type 2 diabetes use a fixed mealtime dose plus a small correction scale written by their clinician.

Should I take my mealtime insulin if I am not eating breakfast?

Usually the mealtime (nutritional) dose is held when you skip the meal, but basal insulin is continued. Whether to give a correction dose for a high reading depends on your written plan. In RABBIT 2, premeal glulisine was held when patients could not eat, while correction insulin was given every 6 hours from the insulin-sensitive column. Ask your prescriber or diabetes team for sick-day and fasting instructions in advance.

How do I combine a carb dose with a sliding scale correction?

Add them. Carb dose = grams of carbohydrate ÷ insulin-to-carb ratio (the 500 rule estimates the ratio as 500 ÷ total daily dose). Example: 45 g of carbs at a ratio of 1:12.5 is 3.6 units, plus a correction of (210 − 120) ÷ 45 = 2 units, for 5.6 → 5.5 units. If your blood sugar is below target, the negative correction reduces the meal dose.

What should I do if my blood sugar is below 70 mg/dL?

Never give correction insulin. Use the 15/15 rule: take 15 g of fast-acting carbohydrate (glucose tablets, 4 oz of juice), recheck in 15 minutes, and repeat until above 70 mg/dL (3.9 mmol/L). Below 54 mg/dL (3.0 mmol/L) is level 2 hypoglycemia. If the person cannot swallow or is unconscious, give glucagon if available and call emergency services.

When is high blood sugar an emergency?

Check ketones when blood sugar is above 240 mg/dL (13.3 mmol/L), especially with type 1 diabetes or illness. The ADA sick-day guide says to call your doctor or go to the ER for moderate or large ketones, fruity breath, vomiting or diarrhea for more than 4 hours, or glucose above 300 mg/dL on two readings despite corrections. Rapid breathing, abdominal pain or confusion with high glucose can be diabetic ketoacidosis.

How is the 1500 rule different from the 1800 rule?

Both estimate how far one unit lowers blood sugar. The 1500 rule (1500 ÷ total daily dose) is for regular human insulin; the 1800 rule (1800 ÷ total daily dose) is for rapid-acting analogs, which drop glucose faster. With 30 units a day, regular insulin gives 50 mg/dL per unit, so 300 mg/dL with a 150 target needs 3 units. These are starting estimates; your own factor should be set from your readings.

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Correction insulin · mg/dL & mmol/L

Sliding Scale Insulin Chart & Calculator

Quick answer

A sliding scale insulin chart gives a dose of rapid- or short-acting insulin for each blood sugar range. A common pattern starts above 150 mg/dL (8.3 mmol/L) and adds 1, 2 or 3 units per 50 mg/dL for a low, moderate or high dose scale — so 247 mg/dL → 2 / 4 / 6 units. Below 70 mg/dL (3.9 mmol/L) give no insulin and treat the low. The ADA recommends correction insulin on top of basal insulin, not a sliding scale alone. Always follow the scale your prescriber wrote.

Enter a blood sugar in mg/dL or mmol/L to read the dose from a low, moderate or high dose scale, or build your own order such as “1 unit per 50 over 150”. The second tab calculates a correction dose from your correction factor, adds a carb dose, and subtracts insulin still active.

Low, moderate and high dose charts in mg/dL and mmol/L
Custom scale builder for any written order
1800, 1500 and 100 rules plus 500-rule carb dosing
Low and high blood sugar safety checks (ADA thresholds)

Last updated October 1, 2026. Thresholds from ADA Standards of Care in Diabetes—2026; published scale from the RABBIT 2 trial. Educational — not a prescription. · sliding scale chart · 1800 rule

Sliding Scale Insulin Calculator

Correction dose from a sliding scale chart, or from your correction factor and carb ratio. Mg/dL or mmol/L.

Blood sugar (mg/dL)

Unit

Scale

Typical use: Total daily insulin about 40–80 units, typical adult eating meals.

247 mg/dL = 13.7 mmol/L · Moderate-dose scale

4 units correction

Above 240 mg/dL (13.3 mmol/L): check blood or urine ketones if you have type 1 diabetes or are unwell. Moderate or large ketones need same-day medical advice.

mg/dL	mmol/L	Units	Note
<70	<3.9	Hold	Hold insulin — treat low blood sugar (15 g fast carbs, recheck in 15 min)
70–150	3.9–8.3	0	No correction needed
151–200	8.4–11.1	2
201–250	11.2–13.9	4
251–300	14.0–16.7	6	Check ketones if type 1 or unwell
301–350	16.8–19.4	8	Check ketones if type 1 or unwell
351–400	19.5–22.2	10	Check ketones if type 1 or unwell
>400	>22.2	12	Give dose and call the prescriber; check ketones

How it was calculated

247 mg/dL = 13.7 mmol/L (÷ 18)
Row on the Moderate-dose scale: 201–250 mg/dL (11.2–13.9 mmol/L)
Correction dose = 4 units of rapid- or short-acting insulin

Educational tool, not a prescription. Always give the dose in your own written order or care plan — insulin type, scale, maximum dose and timing are set by your prescriber.

Sliding scale insulin chart: low, moderate and high dose

Units of rapid- or short-acting insulin per dose. Example scales built on the ADA's suggested start of 150 mg/dL and its low / medium / high split by total daily dose. Your own order may use different numbers.

Insulin sliding scale chart (units per dose)
Blood sugar (mg/dL)	mmol/L	Low-dose (mild)<40 u/day	Moderate-dose40–80 u/day	High-dose>80 u/day	Action
<70	<3.9	Hold — no insulin			15 g fast carbs, recheck in 15 min
70–150	3.9–8.3	0	0	0	No correction
151–200	8.4–11.1	1	2	3	Recheck before next meal
201–250	11.2–13.9	2	4	6	Recheck before next meal
251–300	14.0–16.7	3	6	9	Check ketones if type 1 or unwell
301–350	16.8–19.4	4	8	12	Check ketones if type 1 or unwell
351–400	19.5–22.2	5	10	15	Check ketones if type 1 or unwell
>400	>22.2	6	12	18	Give dose and call the prescriber; check ketones

Low-dose (mild) scale

Also called insulin-sensitive, low intensity

Total daily insulin under about 40 units, older or thin adults, kidney disease, not eating.

Moderate-dose scale

Also called usual, standard, medium

Total daily insulin about 40–80 units, typical adult eating meals.

High-dose scale

Also called insulin-resistant, aggressive

Total daily insulin over about 80 units, obesity, steroids, infection.

How a sliding scale dose is calculated

Every correction scale is a rounded version of one formula: dose = (blood sugar − target) ÷ correction factor, where the correction factor is how many mg/dL one unit lowers your glucose. A scale that adds 1 unit per 50 mg/dL above 150 is a correction factor of 50; 2 units per 50 is a factor of 25. Band charts let a nurse or patient read the dose at a glance instead of doing the division.

Band chart

247 mg/dL → 201–250 row → 4 units (moderate)

Correction factor

1800 ÷ 40 u/day = 45; (250 − 120) ÷ 45 = 2.89 → 3 units

Meal + correction

45 g ÷ 12.5 = 3.6 u; + (210 − 120) ÷ 45 = 2 u → 5.5 units

1. Check blood sugar
Use a meter or CGM before the meal (or every 4–6 hours if not eating). Note whether it reads mg/dL or mmol/L (mmol/L × 18 = mg/dL).
2. Rule out a low
Below 70 mg/dL (3.9 mmol/L): give no insulin. Treat with 15 g of fast carbs and recheck in 15 minutes.
3. Find the row on your ordered scale
Use the low, moderate or high dose column your prescriber chose, or your own "1 unit per X above Y" order.
4. Give the dose with any scheduled insulin
Add the correction to the mealtime dose if one is ordered. Give rapid-acting insulin within 15 minutes of eating, regular insulin 30 minutes before.
5. Recheck and escalate
Recheck before the next meal. Above 240 mg/dL check ketones; above 400 mg/dL or 300 twice despite corrections, call the prescriber.

Units at common blood sugar readings

Look up a reading across all three example scales and the published RABBIT 2 “usual” column.

mg/dL	mmol/L	Low	Moderate	High	RABBIT 2 usual
140	7.8	0	0	0	0
160	8.9	1	2	3	4
180	10.0	1	2	3	4
200	11.1	1	2	3	6
220	12.2	2	4	6	6
247	13.7	2	4	6	8
280	15.6	3	6	9	10
300	16.7	3	6	9	10
350	19.4	4	8	12	12
400	22.2	5	10	15	14
450	25.0	6	12	18	16

Sliding scale insulin chart in mmol/L

For meters that read mmol/L (UK, Europe, Canada, Australia). mmol/L × 18 = mg/dL. In UK hospitals, an IV “sliding scale” is now called a variable rate intravenous insulin infusion (VRIII) and is run by hourly glucose checks — that is a different protocol from these subcutaneous charts.

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

Published scale: the RABBIT 2 supplemental insulin scale

From the RABBIT 2 trial (Umpierrez et al., Diabetes Care 2007), units of glulisine or regular insulin per dose. Patients eating used the “usual” column before meals and at bedtime; patients not eating used the “insulin sensitive” column every 6 hours. The column was moved up for readings persistently above 140 mg/dL and down after any low.

Blood sugar (mg/dL)	mmol/L	Insulin sensitive	Usual	Insulin resistant
141–180	7.9–10.0	2	4	6
181–220	10.1–12.2	4	6	8
221–260	12.3–14.4	6	8	10
261–300	14.5–16.7	8	10	12
301–350	16.8–19.4	10	12	14
351–400	19.5–22.2	12	14	16
>400	>22.2	14	16	18

Result: 66% of patients on scheduled basal-bolus insulin reached a mean glucose under 140 mg/dL, against 38% on sliding scale alone, with no difference in hypoglycemia — one reason the ADA discourages sliding scale insulin without basal insulin.

Correction factor and carb ratio by daily dose

Starting estimates: 1800, 1500, 100 and 500 rules

Units/day	Rapid (mg/dL)	Regular (mg/dL)	mmol/L	Carb ratio (g)
20	90	75	5	25
30	60	50	3.3	16.7
40	45	38	2.5	12.5
50	36	30	2	10
60	30	25	1.7	8.3
80	23	19	1.3	6.3
100	18	15	1	5

Correction factor = how far 1 unit lowers glucose. Carb ratio = grams covered by 1 unit. Adjust from your own readings with your diabetes team.

Rapid-acting vs regular insulin

Timing matters for correction doses

Rapid-acting

Lispro (Humalog, Admelog, Lyumjev), aspart (NovoLog, Fiasp), glulisine (Apidra)

Onset ~15 min · peak ~1 h · lasts ~4 h. Give: within 15 minutes before a meal.

Short-acting (regular)

Humulin R, Novolin R, Actrapid

Onset ~30 min · peak 1.5–2 h · lasts 4–6 h. Give: 30 minutes before a meal.

Avoid repeating rapid-acting corrections within about 2–3 hours, so insulin does not stack. When not eating, the ADA advises correction every 4–6 hours.

Low blood sugar: never give correction insulin

Level 1: 54–69 mg/dL (3.0–3.8 mmol/L). Level 2: below 54 mg/dL (3.0 mmol/L).
15/15 rule: 15 g fast-acting carbs, recheck in 15 minutes, repeat until above 70 mg/dL.
Cannot swallow or unconscious: glucagon if available and call emergency services.

High blood sugar: when to get help

Above 240 mg/dL (13.3 mmol/L): check ketones with type 1 diabetes or illness.
Moderate or large ketones, fruity breath, or vomiting/diarrhea over 4 hours: call or go to the ER.
Above 300 mg/dL on two readings despite corrections, or any reading above 400: call the prescriber.

Sources

American Diabetes Association — 16. Diabetes Care in the Hospital: Standards of Care in Diabetes—2026Correction scale by daily dose, 140–150 mg/dL start, glucose goals, sliding scale alone discouraged, NPO every 4–6 h
Umpierrez GE et al. — RABBIT 2 Trial, Diabetes Care 2007;30(9):2181–2186Published supplemental insulin scale; 66% vs 38% at goal
UCSF Diabetes Teaching Center — Calculating Insulin Dose1800 rule correction factor and 500 rule carb ratio
Evidence to Action (MDCalc) — Review of the Insulin Sensitivity Factor Calculator1500 rule for regular insulin, 1800/1700 for rapid-acting
Preventing Diabetes eLearning (UK) — Correction DosesThe 100 rule for correction factors in mmol/L
Joint British Diabetes Societies — Variable Rate Intravenous Insulin Infusion (VRIII) (PDF)VRIII, "formerly known as sliding scale insulin"
American Diabetes Association — Low Blood Glucose (Hypoglycemia)Below 70 mg/dL and the 15/15 rule
American Diabetes Association — Sick Day Guide (PDF)When to call: ketones, vomiting, glucose above 300 twice
Mayo Clinic — Type 1 diabetes: diagnosis and treatmentInsulin onset, peak and duration; ketones above 240 mg/dL
Endotext (NCBI Bookshelf) — Insulin pharmacology and intensive insulin therapyInsulin action profiles; correction no more than every 4 h on sick days

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Correction insulin · mg/dL & mmol/L

Sliding Scale Insulin Chart & Calculator

Quick answer

Low, moderate and high dose charts in mg/dL and mmol/L
Custom scale builder for any written order
1800, 1500 and 100 rules plus 500-rule carb dosing
Low and high blood sugar safety checks (ADA thresholds)

Sliding Scale Insulin Calculator

Correction dose from a sliding scale chart, or from your correction factor and carb ratio. Mg/dL or mmol/L.

Blood sugar (mg/dL)

Unit

Scale

Typical use: Total daily insulin about 40–80 units, typical adult eating meals.

247 mg/dL = 13.7 mmol/L · Moderate-dose scale

4 units correction

Above 240 mg/dL (13.3 mmol/L): check blood or urine ketones if you have type 1 diabetes or are unwell. Moderate or large ketones need same-day medical advice.

mg/dL	mmol/L	Units	Note
<70	<3.9	Hold	Hold insulin — treat low blood sugar (15 g fast carbs, recheck in 15 min)
70–150	3.9–8.3	0	No correction needed
151–200	8.4–11.1	2
201–250	11.2–13.9	4
251–300	14.0–16.7	6	Check ketones if type 1 or unwell
301–350	16.8–19.4	8	Check ketones if type 1 or unwell
351–400	19.5–22.2	10	Check ketones if type 1 or unwell
>400	>22.2	12	Give dose and call the prescriber; check ketones

How it was calculated

247 mg/dL = 13.7 mmol/L (÷ 18)
Row on the Moderate-dose scale: 201–250 mg/dL (11.2–13.9 mmol/L)
Correction dose = 4 units of rapid- or short-acting insulin

Educational tool, not a prescription. Always give the dose in your own written order or care plan — insulin type, scale, maximum dose and timing are set by your prescriber.

Sliding scale insulin chart: low, moderate and high dose

Insulin sliding scale chart (units per dose)
Blood sugar (mg/dL)	mmol/L	Low-dose (mild)<40 u/day	Moderate-dose40–80 u/day	High-dose>80 u/day	Action
<70	<3.9	Hold — no insulin			15 g fast carbs, recheck in 15 min
70–150	3.9–8.3	0	0	0	No correction
151–200	8.4–11.1	1	2	3	Recheck before next meal
201–250	11.2–13.9	2	4	6	Recheck before next meal
251–300	14.0–16.7	3	6	9	Check ketones if type 1 or unwell
301–350	16.8–19.4	4	8	12	Check ketones if type 1 or unwell
351–400	19.5–22.2	5	10	15	Check ketones if type 1 or unwell
>400	>22.2	6	12	18	Give dose and call the prescriber; check ketones

Low-dose (mild) scale

Also called insulin-sensitive, low intensity

Total daily insulin under about 40 units, older or thin adults, kidney disease, not eating.

Moderate-dose scale

Also called usual, standard, medium

Total daily insulin about 40–80 units, typical adult eating meals.

High-dose scale

Also called insulin-resistant, aggressive

Total daily insulin over about 80 units, obesity, steroids, infection.

How a sliding scale dose is calculated

Band chart

247 mg/dL → 201–250 row → 4 units (moderate)

Correction factor

1800 ÷ 40 u/day = 45; (250 − 120) ÷ 45 = 2.89 → 3 units

Meal + correction

45 g ÷ 12.5 = 3.6 u; + (210 − 120) ÷ 45 = 2 u → 5.5 units

1. Check blood sugar
Use a meter or CGM before the meal (or every 4–6 hours if not eating). Note whether it reads mg/dL or mmol/L (mmol/L × 18 = mg/dL).
2. Rule out a low
Below 70 mg/dL (3.9 mmol/L): give no insulin. Treat with 15 g of fast carbs and recheck in 15 minutes.
3. Find the row on your ordered scale
Use the low, moderate or high dose column your prescriber chose, or your own "1 unit per X above Y" order.
4. Give the dose with any scheduled insulin
Add the correction to the mealtime dose if one is ordered. Give rapid-acting insulin within 15 minutes of eating, regular insulin 30 minutes before.
5. Recheck and escalate
Recheck before the next meal. Above 240 mg/dL check ketones; above 400 mg/dL or 300 twice despite corrections, call the prescriber.

Units at common blood sugar readings

Look up a reading across all three example scales and the published RABBIT 2 “usual” column.

mg/dL	mmol/L	Low	Moderate	High	RABBIT 2 usual
140	7.8	0	0	0	0
160	8.9	1	2	3	4
180	10.0	1	2	3	4
200	11.1	1	2	3	6
220	12.2	2	4	6	6
247	13.7	2	4	6	8
280	15.6	3	6	9	10
300	16.7	3	6	9	10
350	19.4	4	8	12	12
400	22.2	5	10	15	14
450	25.0	6	12	18	16

Sliding scale insulin chart in mmol/L

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

Published scale: the RABBIT 2 supplemental insulin scale

Blood sugar (mg/dL)	mmol/L	Insulin sensitive	Usual	Insulin resistant
141–180	7.9–10.0	2	4	6
181–220	10.1–12.2	4	6	8
221–260	12.3–14.4	6	8	10
261–300	14.5–16.7	8	10	12
301–350	16.8–19.4	10	12	14
351–400	19.5–22.2	12	14	16
>400	>22.2	14	16	18

Correction factor and carb ratio by daily dose

Starting estimates: 1800, 1500, 100 and 500 rules

Units/day	Rapid (mg/dL)	Regular (mg/dL)	mmol/L	Carb ratio (g)
20	90	75	5	25
30	60	50	3.3	16.7
40	45	38	2.5	12.5
50	36	30	2	10
60	30	25	1.7	8.3
80	23	19	1.3	6.3
100	18	15	1	5

Correction factor = how far 1 unit lowers glucose. Carb ratio = grams covered by 1 unit. Adjust from your own readings with your diabetes team.

Rapid-acting vs regular insulin

Timing matters for correction doses

Rapid-acting

Lispro (Humalog, Admelog, Lyumjev), aspart (NovoLog, Fiasp), glulisine (Apidra)

Onset ~15 min · peak ~1 h · lasts ~4 h. Give: within 15 minutes before a meal.

Short-acting (regular)

Humulin R, Novolin R, Actrapid

Onset ~30 min · peak 1.5–2 h · lasts 4–6 h. Give: 30 minutes before a meal.

Avoid repeating rapid-acting corrections within about 2–3 hours, so insulin does not stack. When not eating, the ADA advises correction every 4–6 hours.

Low blood sugar: never give correction insulin

Level 1: 54–69 mg/dL (3.0–3.8 mmol/L). Level 2: below 54 mg/dL (3.0 mmol/L).
15/15 rule: 15 g fast-acting carbs, recheck in 15 minutes, repeat until above 70 mg/dL.
Cannot swallow or unconscious: glucagon if available and call emergency services.

High blood sugar: when to get help

Above 240 mg/dL (13.3 mmol/L): check ketones with type 1 diabetes or illness.
Moderate or large ketones, fruity breath, or vomiting/diarrhea over 4 hours: call or go to the ER.
Above 300 mg/dL on two readings despite corrections, or any reading above 400: call the prescriber.

Sources

American Diabetes Association — 16. Diabetes Care in the Hospital: Standards of Care in Diabetes—2026Correction scale by daily dose, 140–150 mg/dL start, glucose goals, sliding scale alone discouraged, NPO every 4–6 h
Umpierrez GE et al. — RABBIT 2 Trial, Diabetes Care 2007;30(9):2181–2186Published supplemental insulin scale; 66% vs 38% at goal
UCSF Diabetes Teaching Center — Calculating Insulin Dose1800 rule correction factor and 500 rule carb ratio
Evidence to Action (MDCalc) — Review of the Insulin Sensitivity Factor Calculator1500 rule for regular insulin, 1800/1700 for rapid-acting
Preventing Diabetes eLearning (UK) — Correction DosesThe 100 rule for correction factors in mmol/L
Joint British Diabetes Societies — Variable Rate Intravenous Insulin Infusion (VRIII) (PDF)VRIII, "formerly known as sliding scale insulin"
American Diabetes Association — Low Blood Glucose (Hypoglycemia)Below 70 mg/dL and the 15/15 rule
American Diabetes Association — Sick Day Guide (PDF)When to call: ketones, vomiting, glucose above 300 twice
Mayo Clinic — Type 1 diabetes: diagnosis and treatmentInsulin onset, peak and duration; ketones above 240 mg/dL
Endotext (NCBI Bookshelf) — Insulin pharmacology and intensive insulin therapyInsulin action profiles; correction no more than every 4 h on sick days

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mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18

mmol/L	≈ mg/dL	Low	Moderate	High
7	126	0	0	0
8	144	0	0	0
10	180	1	2	3
12	216	2	4	6
14	252	3	6	9
16	288	3	6	9
18	324	4	8	12
20	360	5	10	15
22	396	5	10	15
25	450	6	12	18