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Free cat calorie calculator: estimate how many calories your cat needs per day from weight and life stage using veterinary-style RER (70 × kg0.75) and MER multipliers. Convert kcal to wet cans, dry cups, and treat budgets. Educational — always confirm with your vet. Compare dog calories separately (different factors).
Last updated: May 24, 2026
How old is your cat in human years? Cat age calculator
Typical adult cats often fall near 8–12 lb (3.5–5.5 kg).
Estimate
About 218 kcal/day resting need (RER) × 1.2 (Adult neutered (maintenance)) → roughly 261 kcal/day as a maintenance-style estimate (MER).
Weight
10 lb · 4.5 kg
RER
218 kcal/day
Factor
× 1.2
MER (style)
261 kcal/day
Adult neutered (maintenance)
Food math (illustrative)
~3.3 × 80 kcal cans · ~0.7 cups dry (350 kcal/cup) · treats ≤26 kcal (10%)
218
kcal/day at rest
261
Compare to food label kcal
~3.3
Treats ≤26 kcal (10%)
10 lb · neutered
261 kcal
12 lb · neutered
299 kcal
5 lb · young kitten
323 kcal
14 lb · weight loss
224 kcal
RER = 70 × (weight_kg)0.75
MER = RER × life_stage_factor
RER (kcal/day) ≈ 70 × (body weight in kg)^0.75 — standard small-animal veterinary form (also written as 30 × BW_kg + 70 for cats roughly 2–6 kg).
Worked (10 lb): 4.5 kg → RER 218 kcal; ×1.2 = 261 kcal MER. Intact same weight: 305 kcal (×1.4).
| Life stage | × RER | MER (kcal/day) | Note |
|---|---|---|---|
| Kitten (rapid growth, ~0–4 mo) | ×2.5 | 545 | High growth demand; feed kitten formula per vet |
| Kitten (juvenile, ~4–12 mo) | ×2 | 436 | Slowing growth; transition toward adult targets |
| Adult neutered (maintenance) | ×1.2 | 262 | Common indoor spayed/neutered cat default |
| Adult intact (maintenance) | ×1.4 | 305 | Higher than neutered; roaming/intact metabolism |
| Overweight — weight loss (vet-supervised) | ×0.8 | 174 | Below RER; monitor BCS — hepatic lipidosis risk if too fast |
| Late pregnancy (approximate) | ×1.6 | 349 | Rises through gestation; individualized by week |
| Lactation (peak-ish average) | ×2.5 | 545 | Litter size drives demand; often highest MER period |
RER at 10 lb = 218 kcal for all rows; only the multiplier changes.
| Size | Weight | MER @ neutered ×1.2 (approx.) | Note |
|---|---|---|---|
| 8 lb adult | 8 lb | 221 kcal/day | BCS may require adjustment |
| 10 lb adult | 10 lb | 261 kcal/day | BCS may require adjustment |
| 12 lb adult | 12 lb | 299 kcal/day | BCS may require adjustment |
| Food type | Example kcal | Portions @ 261 kcal MER |
|---|---|---|
| Wet food can (typical) | 80 kcal per 3 oz can | ~3.3 units/day |
| Wet food can (richer) | 100 kcal per 3 oz can | ~2.6 units/day |
| Dry kibble | 350 kcal per cup (label varies) | ~0.7 units/day |
| Treats (limit) | 10 kcal per small treat — budget ≤10% MER | ≤26 kcal/day total |
Weight: 10 lb = 4.5 kg
RER = 70 × (4.5)^0.75 ≈ 218 kcal/day
MER = 218 × 1.2 = 261 kcal/day
~3.3 wet cans (80 kcal each) or ~0.7 cups dry (350 kcal/cup) — split into 2–4 meals; confirm with your vet.
Share it with other cat parents planning feeding with their veterinarian.
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