How much Tylenol (acetaminophen) for an 18 kg child at 15 mg/kg?

Default pediatric demo: 18 kg × 15 mg/kg = 270 mg per dose (rounded, max 1000 mg/dose). Daily ceiling: min(3000 mg OTC, 18 × 75 mg/kg/day) = 1350 mg. Math allows up to ~5 equal doses in 24 h only if spaced per label (often every 4–6 h). At 160 mg/5 mL (32 mg/mL): 270 mg ≈ 8.4 mL per dose with the packaged syringe. Adult 500 mg: floor(3000÷500)=6 dose ceiling; 1000 mg → 3. 40 lb × 10 mg/kg: 181 mg. 25 kg × 15 mg/kg: 375 mg, daily 1875 mg. Educational visit-prep only — not prescribing, triage, or poison-control replacement.

Is Tylenol the same as acetaminophen?

Yes in the US: Tylenol is a brand of acetaminophen (APAP). Paracetamol is the same molecule in many countries. Always read the Drug Facts “Active ingredient” line—store brands, cold/flu combos, and prescription pain pills may list acetaminophen without the Tylenol name.

How much acetaminophen can an adult take per day?

Many US patient resources plan around 3000 mg total in 24 hours from all sources for unsupervised OTC use. Some labels still reference up to 4000 mg/day only with medical direction. This calculator uses 3000 mg as a conservative ceiling. Example: 500 mg per dose → floor(3000÷500)=6 equal doses only if 4–6 h spacing and labeling allow—often fewer in practice.

How is pediatric Tylenol dose calculated by weight?

Common teaching: 10–15 mg/kg per dose every 4–6 hours PRN, capped at 1000 mg per dose. Daily total: min(3000 mg OTC ceiling, weight×75 mg/kg/day). Default demo: 18 kg × 15 mg/kg = 270 mg per dose; daily min(3000, 18×75)=1350 mg; up to floor(1350÷270)=5 doses if spaced correctly. Convert mg to mL using your bottle concentration (e.g., 160 mg/5 mL = 32 mg/mL).

Why must I count combination cold and flu medicines?

Products like DayQuil, NyQuil, Theraflu, Tylenol PM, and Excedrin contain acetaminophen plus other drugs. Prescription opioids (Norco, Percocet) also include APAP. Stacking a “regular” Tylenol dose with a cold syrup is a leading cause of accidental overdose—read every label and add milligrams manually.

What liquid concentration should I use for children?

Common children's suspensions: 160 mg/5 mL (32 mg/mL) or 120 mg/5 mL (24 mg/mL). Infant products historically used higher mg/mL—concentrations changed after safety concerns. Never use a kitchen spoon; use the oral syringe packaged with your specific bottle. 270 mg at 32 mg/mL ≈ 8.4 mL.

Can I use this calculator for infants under 12 pounds?

No for weights below ~5.5 kg (about 12 lb)—this tool blocks them. Infant dosing depends on age, concentration, and clinician charts. Call your pediatrician or pharmacist for written infant instructions rather than extrapolating from older-child mg/kg math.

What are warning signs of acetaminophen overdose?

Early: nausea, vomiting, sweating, not feeling well. Liver injury may progress over 24–72 hours with right upper abdominal pain, jaundice, confusion. Suspected overdose is an emergency—US Poison Help 1-800-222-1222; do not wait for symptoms to “prove” toxicity. N-acetylcysteine is time-sensitive antidote.

Does alcohol change acetaminophen safety?

Chronic alcohol use and binge drinking deplete glutathione, lowering the threshold for hepatotoxicity. FDA labeling warns heavy drinkers (3+ drinks/day) to consult a clinician before APAP. If you drink regularly, ask your pharmacist for a personal daily maximum—may be well below 3000 mg.

How does acetaminophen compare to ibuprofen (Motrin/Advil)?

APAP is not an NSAID—different liver vs GI/kidney risk profile. Pediatric APAP: 10–15 mg/kg q4–6h; ibuprofen: 5–10 mg/kg q6–8h. Adult OTC ceilings: ~3000 mg APAP vs ~1200 mg ibuprofen. Alternating them requires a written clinician schedule—do not stack both every hour without guidance.

Why does my max doses per day not match the package?

We show floor(daily ceiling ÷ single dose)—arithmetic only. Real limits also require minimum hours between doses (often 4–6), age restrictions, and combination products. A 500 mg adult might math to 6 doses but label may say 4 doses maximum—follow Drug Facts, not this ceiling alone.

Is 1000 mg per dose safe for adults?

Some adults take two 500 mg extra-strength tablets (1000 mg) per dose when appropriate per label. With 3000 mg/day ceiling, math allows only 3 such doses in 24 h—and spacing rules may permit fewer. Never take 1000 mg without confirming your specific product label and liver risk factors.

Can I take Tylenol with warfarin?

Short-term APAP at standard doses is often acceptable, but prolonged regular use or high doses can raise INR in some patients. If you take warfarin, report APAP use to your anticoagulation team and monitor INR—pharmacist review recommended.

What about extended-release arthritis Tylenol (650 mg)?

Extended-release products have different timing (often every 8 hours) and must not be crushed or chewed. Do not add immediate-release doses on top of ER doses without label approval—double-counting toward daily max causes overdose risk.

Is this calculator a substitute for a pharmacist or doctor?

No. Educational visit-prep only. It cannot verify your bottle concentration, allergies, liver function, other medications, or the correct formulation for your child's age. Dosing decisions belong to you and your care team with the actual product in hand.

theCalcs

Get Custom Solution

Loading calculators...

Fetching calculator categories and tools for this section.

Go to Calculators Browse Calculators

Loading the page...

Preparing tools and content for you. This usually takes a second.

Go Home Browse Calculators

theCalcs

Get Custom Solution

OTC analgesic / antipyretic

Tylenol Dosage Calculator — Acetaminophen Adult & Pediatric mg/kg

Quick answer — acetaminophen (APAP)

18 kg child × 15 mg/kg: 270 mg per dose (~8.4 mL at 32 mg/mL), daily cap 1350 mg, up to ~5 doses if spaced per label. Adult 500 mg: 6-dose math on 3000 mg/day from all APAP products. Count cold/flu combos — not medical advice.

Adult OTC ceiling: 3000 mg/24 h (conservative)
Pediatric per dose: 10–15 mg/kg q4–6h PRN
Pediatric daily: min(3000 mg, weight × 75 mg/kg/day)
Related: Ibuprofen dose · mg to mL

Estimate acetaminophen (APAP) — brand example Tylenol — with adult strength selection and pediatric weight-based mg/kg. Educational only; verify your bottle and Drug Facts.

Last updated: October 9, 2026

Adult 325–1000 mg with 3000 mg/day OTC planning ceiling

Pediatric mg/kg, liquid concentration, and hidden APAP tables

Liver toxicity risk factors and poison-control guidance

Count every APAP source

Cold medicines, sleep aids, and prescription pain combos contain acetaminophen. Overdose can cause liver injury—suspected overdose is an emergency.

Tylenol Dosage Calculator (Acetaminophen)

Acetaminophen / APAP (brand example: Tylenol). Educational only—not a prescription.

Who is this for?

Body weight

Units

Dose factor (mg per kg per dose)

Results

Single dose

270 mg

Conservative daily ceiling

1350 mg

OTC planning reference (all APAP sources combined)

Weight (kg): 18

mg/kg used: 15

Math ceiling only

Up to ~5 equal doses in 24 h if each dose is 270 mg

Real schedules must respect minimum hours between doses on your label (often 4–6 hours) and liver safety. Never exceed labeled maximums or your clinician's plan.

Pediatric acetaminophen is often discussed as about 10–15 mg/kg per dose every 4–6 hours as needed, with total daily milligrams capped by both weight-based limits and OTC daily limits.
Infant concentrates (mg/mL) differ from children's liquids—use only the dosing device for your bottle and double-check the concentration printed on the package.
Never give adult tablets to young children by breaking them without pharmacist or clinician instruction.

Acetaminophen overdose can cause liver injury. Alcohol use, fasting, warfarin interaction concerns, and chronic liver disease change risk. Seek emergency care for suspected overdose or overdose line per your country.

Acetaminophen scenarios (computed)

Scenario	Mode	Single dose	Daily ceiling	Max doses (math)	Liquid (32 mg/mL)
Child 18 kg × 15 mg/kg	Pediatric weight	270 mg	1350 mg	~5	≈ 8.4 mL @ 32 mg/mL
Adult 500 mg per dose	Adult OTC	500 mg	3000 mg	~6	—
Adult 1000 mg per dose	Adult OTC	1000 mg	3000 mg	~3	—
40 lb child × 10 mg/kg	Pediatric weight	181 mg	1361 mg	~7	≈ 5.7 mL @ 32 mg/mL
25 kg × 15 mg/kg	Pediatric weight	375 mg	1875 mg	~5	≈ 11.7 mL @ 32 mg/mL

Acetaminophen dosing reference

Educational tables — always follow your specific Drug Facts panel.

Adult single-dose strengths

Strength	Typical use	Note
325 mg	Regular strength tablets/capsules	Often 1–2 tablets per dose per label
500 mg	Extra strength — most common adult OTC	3000 mg/day ÷ 500 = 6 dose math ceiling
650 mg	Arthritis / extended-release examples	Follow ER spacing — not interchangeable with IR
1000 mg	Two 500 mg tablets when appropriate	3000 mg/day ÷ 1000 = 3 dose math ceiling

Pediatric mg/kg teaching

Dose	When	Interval
10 mg/kg	Milder end of teaching range	q4–6h PRN
12.5 mg/kg	Mid-range fever/pain	q4–6h PRN
15 mg/kg	Common per-dose maximum in references	q4–6h PRN; cap 1000 mg/dose
75 mg/kg/day	Weight-based daily teaching limit	Also capped at 3000 mg OTC ceiling

Dosing intervals

Population	Interval	Daily note
Adult OTC	Every 4–6 hours PRN	Count all APAP sources toward 3000 mg
Pediatric OTC	Every 4–6 hours PRN	min(3000, weight×75 mg) daily ceiling
Extended-release	Label-specific (often q8h)	Never crush ER products

Liquid concentrations (verify your bottle)

Product type	mg/mL	Warning
Infant drops (historical 80 mg/0.8 mL)	100 mg/mL	Concentrations changed — verify current bottle
Children's suspension (common)	32 mg/mL (160 mg/5 mL)	Use packaged oral syringe only
Children's suspension (alternate)	24 mg/mL (120 mg/5 mL)	Do not swap concentrations without recalculating mL

Hidden acetaminophen sources

Product type	Examples	Risk
Cold/flu multisymptom	DayQuil, NyQuil, Theraflu	APAP listed on panel — stacks with Tylenol
Sleep aids	Tylenol PM, many PM cold products	APAP + diphenhydramine
Migraine combos	Excedrin (APAP + aspirin + caffeine)	Multiple analgesics
Prescription pain	Norco, Percocet, Vicodin	APAP in opioid combos — daily limit critical

Worked example: 18 kg child at 15 mg/kg → 270 mg

Weight: 18 kg
Per-dose: 18.0 kg × 15 mg/kg = 270.0 mg → round & cap → 270 mg
Daily from weight: 18.0 × 75 = 1350 mg/kg/day
Daily ceiling: min(3000, 1350) = 1350 mg
Dose count ceiling: floor(1350 ÷ 270) = 5 doses (if spaced per label)

Adult OTC: pick single dose (325–1000 mg); conservative 24 h total from all sources = 3000 mg unless directed otherwise.
Adult dose-count ceiling (math only): floor(3000 ÷ single dose mg) — still obey 4–6 h spacing and label max doses.
Child per dose: weight (kg) × mg/kg (10–15), round, cap at 1000 mg per dose.
Child daily: min(3000 mg, weight × 75 mg/kg/day); dose-count ceiling = floor(daily ÷ per-dose mg).
Liquid: mg ÷ bottle concentration (e.g. 160 mg/5 mL → 32 mg/mL) = mL per dose — use packaged oral syringe only.

At 32 mg/mL (160 mg/5 mL): 270 mg ÷ 32 ≈ 8.4 mL per dose — use packaged syringe.

Accuracy & limitations

Educational visit-prep only — not prescribing, triage, or poison-control replacement.
Uses 3000 mg/day conservative OTC ceiling from all APAP sources; labels and clinicians may differ.
Pediatric mg/kg (10–15) and 75 mg/kg/day caps are teaching values — confirm with Drug Facts and your clinician.
Blocks weights under ~5.5 kg; infant concentrates and age limits need pharmacist or pediatrician guidance.
Does not check liver disease, alcohol use, warfarin, allergies, or combination products in your cabinet.

Toxicity risk factors

Factor	Effect	Action
Exceeding daily max	Hepatotoxicity	Poison control / ER if suspected overdose
Chronic alcohol use	Lower threshold for liver injury	Ask clinician for personal limit
Fasting / acute illness	Glutathione depletion	Avoid repeated high doses when not eating
Liver disease	Impaired metabolism	Often avoid or use clinician-directed lower max
Warfarin co-use	INR elevation risk at high APAP doses	Monitor INR; pharmacist review

Acetaminophen vs ibuprofen

Aspect	Acetaminophen	Ibuprofen
Drug class	Non-NSAID analgesic/antipyretic	NSAID
OTC adult daily ceiling (US teaching)	3000 mg conservative	1200 mg typical
Pediatric mg/kg	10–15 mg/kg q4–6h	5–10 mg/kg q6–8h
Key risks	Liver toxicity (overdose)	GI bleed, kidney effects
Alternating	Only on written clinician schedule	Do not improvise stacking

3000 vs 4000 mg

Daily ceiling context

This tool uses 3000 mg for OTC self-care. Up to 4000 mg may appear only with medical supervision.

Spacing matters

Not just milligrams

Six 500 mg doses math out of 3000 mg—but 4–6 h spacing over 24 h often allows fewer than six in practice.

Poison Help

US: 1-800-222-1222

Suspected overdose warrants immediate poison control or emergency care—do not wait for jaundice.

References & disclaimer

FDA — OTC acetaminophen Drug Facts labelingDose, interval, liver warning, combination product guidance.
Poison Help (US) — poison.org1-800-222-1222 for medication overdose guidance.
American Academy of Pediatrics — fever management resourcesWeight-based antipyretic education for caregivers.

Educational disclaimer: This calculator applies simplified acetaminophen teaching limits for learning and caregiver prep. It does not verify bottle concentration, prescribe medication, or replace your pharmacist, pediatrician, or poison control. Do not dose infants or overdose situations from this page.

Frequently Asked Questions

Found this helpful?

Share for safe OTC acetaminophen education.

Share This Calculator

Help others discover this useful tool

Copy Link

https://www.thecalcs.com/calculators/medical-health/tylenol-dosage-calculator

Share on Social Media

X Facebook LinkedIn WhatsApp

Share via Email

Suggested hashtags: #Tylenol #Acetaminophen #Pediatrics #OTC #Calculator

Related Calculators

Ibuprofen Dosage Calculator

NSAID OTC limits and pediatric mg/kg — compare drug class risks.

Use Calculator

Melatonin Dosage Calculator

Pediatric sleep aid weight-based estimates (educational).

Use Calculator

Maintenance Fluid Calculator

4-2-1 pediatric hourly fluids for dehydration context.

Use Calculator

Warfarin Dose Adjustment Calculator

INR titration — APAP interaction awareness.

Use Calculator

Standard Drink Calculator

Alcohol unit math — relevant to APAP liver risk.

Use Calculator

GFR Calculator

Kidney function in polypharmacy safety context.

Use Calculator

theCalcs

Get Custom Solution

Loading calculators...

Fetching calculator categories and tools for this section.

Go to Calculators Browse Calculators

theCalcs

Get Custom Solution

OTC analgesic / antipyretic

Tylenol Dosage Calculator — Acetaminophen Adult & Pediatric mg/kg

Quick answer — acetaminophen (APAP)

Adult OTC ceiling: 3000 mg/24 h (conservative)
Pediatric per dose: 10–15 mg/kg q4–6h PRN
Pediatric daily: min(3000 mg, weight × 75 mg/kg/day)
Related: Ibuprofen dose · mg to mL

Estimate acetaminophen (APAP) — brand example Tylenol — with adult strength selection and pediatric weight-based mg/kg. Educational only; verify your bottle and Drug Facts.

Last updated: October 9, 2026

Adult 325–1000 mg with 3000 mg/day OTC planning ceiling

Pediatric mg/kg, liquid concentration, and hidden APAP tables

Liver toxicity risk factors and poison-control guidance

Count every APAP source

Cold medicines, sleep aids, and prescription pain combos contain acetaminophen. Overdose can cause liver injury—suspected overdose is an emergency.

Tylenol Dosage Calculator (Acetaminophen)

Acetaminophen / APAP (brand example: Tylenol). Educational only—not a prescription.

Who is this for?

Body weight

Units

Dose factor (mg per kg per dose)

Results

Single dose

270 mg

Conservative daily ceiling

1350 mg

OTC planning reference (all APAP sources combined)

Weight (kg): 18

mg/kg used: 15

Math ceiling only

Up to ~5 equal doses in 24 h if each dose is 270 mg

Real schedules must respect minimum hours between doses on your label (often 4–6 hours) and liver safety. Never exceed labeled maximums or your clinician's plan.

Pediatric acetaminophen is often discussed as about 10–15 mg/kg per dose every 4–6 hours as needed, with total daily milligrams capped by both weight-based limits and OTC daily limits.
Infant concentrates (mg/mL) differ from children's liquids—use only the dosing device for your bottle and double-check the concentration printed on the package.
Never give adult tablets to young children by breaking them without pharmacist or clinician instruction.

Acetaminophen scenarios (computed)

Scenario	Mode	Single dose	Daily ceiling	Max doses (math)	Liquid (32 mg/mL)
Child 18 kg × 15 mg/kg	Pediatric weight	270 mg	1350 mg	~5	≈ 8.4 mL @ 32 mg/mL
Adult 500 mg per dose	Adult OTC	500 mg	3000 mg	~6	—
Adult 1000 mg per dose	Adult OTC	1000 mg	3000 mg	~3	—
40 lb child × 10 mg/kg	Pediatric weight	181 mg	1361 mg	~7	≈ 5.7 mL @ 32 mg/mL
25 kg × 15 mg/kg	Pediatric weight	375 mg	1875 mg	~5	≈ 11.7 mL @ 32 mg/mL

Acetaminophen dosing reference

Educational tables — always follow your specific Drug Facts panel.

Adult single-dose strengths

Strength	Typical use	Note
325 mg	Regular strength tablets/capsules	Often 1–2 tablets per dose per label
500 mg	Extra strength — most common adult OTC	3000 mg/day ÷ 500 = 6 dose math ceiling
650 mg	Arthritis / extended-release examples	Follow ER spacing — not interchangeable with IR
1000 mg	Two 500 mg tablets when appropriate	3000 mg/day ÷ 1000 = 3 dose math ceiling

Pediatric mg/kg teaching

Dose	When	Interval
10 mg/kg	Milder end of teaching range	q4–6h PRN
12.5 mg/kg	Mid-range fever/pain	q4–6h PRN
15 mg/kg	Common per-dose maximum in references	q4–6h PRN; cap 1000 mg/dose
75 mg/kg/day	Weight-based daily teaching limit	Also capped at 3000 mg OTC ceiling

Dosing intervals

Population	Interval	Daily note
Adult OTC	Every 4–6 hours PRN	Count all APAP sources toward 3000 mg
Pediatric OTC	Every 4–6 hours PRN	min(3000, weight×75 mg) daily ceiling
Extended-release	Label-specific (often q8h)	Never crush ER products

Liquid concentrations (verify your bottle)

Product type	mg/mL	Warning
Infant drops (historical 80 mg/0.8 mL)	100 mg/mL	Concentrations changed — verify current bottle
Children's suspension (common)	32 mg/mL (160 mg/5 mL)	Use packaged oral syringe only
Children's suspension (alternate)	24 mg/mL (120 mg/5 mL)	Do not swap concentrations without recalculating mL

Hidden acetaminophen sources

Product type	Examples	Risk
Cold/flu multisymptom	DayQuil, NyQuil, Theraflu	APAP listed on panel — stacks with Tylenol
Sleep aids	Tylenol PM, many PM cold products	APAP + diphenhydramine
Migraine combos	Excedrin (APAP + aspirin + caffeine)	Multiple analgesics
Prescription pain	Norco, Percocet, Vicodin	APAP in opioid combos — daily limit critical

Worked example: 18 kg child at 15 mg/kg → 270 mg

Weight: 18 kg
Per-dose: 18.0 kg × 15 mg/kg = 270.0 mg → round & cap → 270 mg
Daily from weight: 18.0 × 75 = 1350 mg/kg/day
Daily ceiling: min(3000, 1350) = 1350 mg
Dose count ceiling: floor(1350 ÷ 270) = 5 doses (if spaced per label)

Adult OTC: pick single dose (325–1000 mg); conservative 24 h total from all sources = 3000 mg unless directed otherwise.
Adult dose-count ceiling (math only): floor(3000 ÷ single dose mg) — still obey 4–6 h spacing and label max doses.
Child per dose: weight (kg) × mg/kg (10–15), round, cap at 1000 mg per dose.
Child daily: min(3000 mg, weight × 75 mg/kg/day); dose-count ceiling = floor(daily ÷ per-dose mg).
Liquid: mg ÷ bottle concentration (e.g. 160 mg/5 mL → 32 mg/mL) = mL per dose — use packaged oral syringe only.

At 32 mg/mL (160 mg/5 mL): 270 mg ÷ 32 ≈ 8.4 mL per dose — use packaged syringe.

Accuracy & limitations

Educational visit-prep only — not prescribing, triage, or poison-control replacement.
Uses 3000 mg/day conservative OTC ceiling from all APAP sources; labels and clinicians may differ.
Pediatric mg/kg (10–15) and 75 mg/kg/day caps are teaching values — confirm with Drug Facts and your clinician.
Blocks weights under ~5.5 kg; infant concentrates and age limits need pharmacist or pediatrician guidance.
Does not check liver disease, alcohol use, warfarin, allergies, or combination products in your cabinet.

Toxicity risk factors

Factor	Effect	Action
Exceeding daily max	Hepatotoxicity	Poison control / ER if suspected overdose
Chronic alcohol use	Lower threshold for liver injury	Ask clinician for personal limit
Fasting / acute illness	Glutathione depletion	Avoid repeated high doses when not eating
Liver disease	Impaired metabolism	Often avoid or use clinician-directed lower max
Warfarin co-use	INR elevation risk at high APAP doses	Monitor INR; pharmacist review

Acetaminophen vs ibuprofen

Aspect	Acetaminophen	Ibuprofen
Drug class	Non-NSAID analgesic/antipyretic	NSAID
OTC adult daily ceiling (US teaching)	3000 mg conservative	1200 mg typical
Pediatric mg/kg	10–15 mg/kg q4–6h	5–10 mg/kg q6–8h
Key risks	Liver toxicity (overdose)	GI bleed, kidney effects
Alternating	Only on written clinician schedule	Do not improvise stacking

3000 vs 4000 mg

Daily ceiling context

This tool uses 3000 mg for OTC self-care. Up to 4000 mg may appear only with medical supervision.

Spacing matters

Not just milligrams

Six 500 mg doses math out of 3000 mg—but 4–6 h spacing over 24 h often allows fewer than six in practice.

Poison Help

US: 1-800-222-1222

Suspected overdose warrants immediate poison control or emergency care—do not wait for jaundice.

References & disclaimer

FDA — OTC acetaminophen Drug Facts labelingDose, interval, liver warning, combination product guidance.
Poison Help (US) — poison.org1-800-222-1222 for medication overdose guidance.
American Academy of Pediatrics — fever management resourcesWeight-based antipyretic education for caregivers.