Cat Feeding Calculator
For a 10 lb (4.54 kg) spayed or neutered adult cat on a food that prints 400 kcal per 100 g, the daily target is 261 kcal — 65.3 g a day, 32.6 g per meal at two meals, which is 2.72 scoops per meal with a 12 g scoop, or 0.77 of an 85 g can a day.
Enter your cat's details and your food's label numbers
Use a measured weight. Supported range is 4–25 lb (1.8–11.3 kg).
These are the lower ends of the published ranges; the factor table below says what the ranges are and what they are not.
The daily total is unchanged by this. It only changes how the day is divided.
Labels print this in several forms — kcal/kg, kcal per cup, kcal per can. The conversion for each form is spelled out under “Reading the label” below.
The drained or net weight on the tin, not the kcal. Used for the cans-per-day line.
Set it to 0 if you weigh food on a scale and never use a scoop. Weigh it once — the method is below.
Used only for the “days per pack” line, so you know when to reorder.
Everything is calculated in your browser. The numbers you type are not uploaded and not stored.
What goes in the bowl
Food per day
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Enter a weight to see the daily amount and the per-meal split.
The number that matters is the one you can weigh. A daily calorie target is an estimate; the grams you put on the scale are the instruction. This page carries the arithmetic all the way from body weight to scoops per meal and days per bag, and prints every conversion in between, so a disagreement with your vet is about one step you can both point at rather than about a black box.
A calorie number is not a feeding instruction. Put your own numbers in below: the same arithmetic recomputes live, and every step is printed underneath so you can check it on paper.
Constants this page uses, and where each one comes from
| Constant | What it is | Named source |
|---|---|---|
| 70 | RER scaling constant, 70 × kg0.75 | Association for Pet Obesity Prevention |
| 0.75 | exponent applied to body weight in kilograms | Association for Pet Obesity Prevention |
| 1.0 | factor band for sedentary or prone to weight gain | Association for Pet Obesity Prevention |
| 1.2–1.4 | factor band for typical adult, spayed or neutered | Association for Pet Obesity Prevention |
| 1.4–1.6 | factor band for typical adult, intact | Association for Pet Obesity Prevention |
Where to start
Start with the Cat Calorie Calculator: it needs only a weight and a condition, so it returns a daily calorie range before you have read a single food label. That range is the input every other Feline tool expects, including this page.
The chain of arithmetic, every symbol defined
Seven quantities, each computed from the one above it. Nothing on this page uses a number that is not either printed here or taken from your own input.
Step 1 — resting energy requirement
RER = 70 × W0.75
W is body weight in kilograms. A 4.5359 kg cat has an RER of 70 × 4.53590.75 ≈ 217.6 kcal/day. RER is what the body spends staying alive at complete rest, before any activity allowance.
Step 2 — the daily allowance
kcal/day = RER × f (rounded to the nearest whole kcal)
f is the activity-and-neuter factor from the table below. At f = 1.2 the example cat lands on 217.6 × 1.2 = 261.1, shown as 261 kcal/day. Every figure further down is computed from that rounded whole number, so the printed numbers chain without drift.
Step 3 — calories to grams
g/day = kcal/day ÷ D × 100
D is the energy density in kcal per 100 g. 261 ÷ 400 × 100 = 65.25 g/day, printed as 65.3 g. Gram figures carry one decimal and are computed from the unrounded value, so a hand-check can differ from the printed figure by 0.1 g. That is rounding, not disagreement.
Step 4 — grams to meals
g/meal = g/day ÷ n
n is meals per day, 1 to 4 on this page. 65.25 ÷ 2 = 32.6 g per meal.
Step 5 — grams to scoops
scoops/meal = g/meal ÷ s
s is the weight of one level scoop of your food, in grams. 32.625 ÷ 12 = 2.72 scoops per meal. If you do not use a scoop, set s to zero and this line disappears.
Step 6 — grams to cans
cans/day = g/day ÷ c
c is the net weight of one can or pouch in grams. 65.25 ÷ 85 = 0.77 cans/day.
Step 7 — how long the pack lasts
days per pack = P ÷ g/day
P is the weight of the pack in grams: 1,500 for a 1.5 kg bag, or cans × c for a case. 3,000 ÷ 65.25 = 46.0 days for a 3 kg bag at these inputs.
| Symbol | Means | Unit | Where it comes from |
|---|---|---|---|
| W | Body weight | kg | Your input, converted from lb if needed |
| RER | Resting energy requirement | kcal/day | Step 1 |
| f | Activity and neuter factor | × RER | The factor table below |
| D | Energy density of the food | kcal per 100 g | Your food's label |
| n | Meals per day | count | Your input |
| s | Weight of one level scoop | g | You weigh it once |
| c | Net weight of one can or pouch | g | Your food's label |
| P | Weight of the pack you buy | g | Bag size, or cans × c |
Two exact conversion constants are used and nothing else: 1 lb = 0.45359237 kg, and 1 oz = 28.349523125 g.
The activity factor, and what it is not
Three published categories, each with a range. This page uses the lower end of each range as a single working factor, because a single factor gives you a single number you can put on a scale. The ranges are printed so you can see how much room sits above the number you were given.
| Category | Published range | Factor used here | kcal/day at 10 lb | g/day at 400 kcal/100 g |
|---|---|---|---|---|
| Sedentary or prone to weight gain | 1.0× RER | 1.0 | 218 | 54.5 |
| Typical adult, spayed or neutered | 1.2–1.4× RER | 1.2 | 261 | 65.3 |
| Typical adult, intact | 1.4–1.6× RER | 1.4 | 305 | 76.3 |
What the factor is not: it is not a minimum safe intake, it is not a maximum, and it is not adjusted again for age, breed, or whether the cat goes outdoors. A cat that is already gaining on the 1.2 factor does not need a fourth category — it needs the 1.0 line and a weekly weigh-in.
The answer table — every weight on one page
Fixed assumptions, printed on the table so nothing is hidden: factor 1.2 (typical adult, spayed or neutered), 400 kcal per 100 g, two meals a day, 85 g cans. If any of those four is different for your cat, the calculator above will give you the right line instead.
| Weight | kg | RER | kcal/day | g/day | g/meal (2) | 85 g cans/day |
|---|---|---|---|---|---|---|
| 6 lb | 2.72 | 148.3 | 178 | 44.5 | 22.3 | 0.52 |
| 8 lb | 3.63 | 184.0 | 221 | 55.3 | 27.6 | 0.65 |
| 10 lb | 4.54 | 217.6 | 261 | 65.3 | 32.6 | 0.77 |
| 12 lb | 5.44 | 249.4 | 299 | 74.8 | 37.4 | 0.88 |
| 14 lb | 6.35 | 280.0 | 336 | 84.0 | 42.0 | 0.99 |
| 16 lb | 7.26 | 309.5 | 371 | 92.8 | 46.4 | 1.09 |
| 18 lb | 8.16 | 338.1 | 406 | 101.5 | 50.8 | 1.19 |
| 20 lb | 9.07 | 365.9 | 439 | 109.8 | 54.9 | 1.29 |
Above about 20 lb the arithmetic still works, but the question stops being a feeding question and becomes a body-condition question. This page will not answer that one.
Reading the label: four forms, one density
The calculator needs one number, kcal per 100 g. Labels in the wild print it four different ways. Each conversion below is exact and takes one line.
If the label says kcal per kg
D = kcal/kg ÷ 10
4,000 kcal/kg ÷ 10 = 400 kcal per 100 g
If the label says kilojoules per 100 g
D = kJ ÷ 4.184
1,673.6 kJ per 100 g ÷ 4.184 = 400 kcal per 100 g
If the label says kcal per cup
grams per cup = kcal per cup ÷ D × 100
400 kcal per cup ÷ 400 × 100 = 100 g per cup, so a 65.25 g day is 0.65 cups
If the label says kcal per can
D = kcal per can ÷ can weight in g × 100
80 kcal per 85 g can ÷ 85 × 100 = 94.1 kcal per 100 g
The fourth one is where wet-food arithmetic most often goes wrong. An 85 g can at 80 kcal works out at 94 kcal per 100 g — roughly a quarter of a typical dry food's density — which is why a wet-fed cat needs a much bigger pile in the bowl for the same calories. The calculator handles that as long as you give it the density, not the can count.
Worked example — nine lines you can check on a calculator
10 lb spayed female, 400 kcal per 100 g dry food, two meals, 12 g scoop, 85 g cans, 3 kg bag.
| Step | Calculation | Result |
|---|---|---|
| 1. Convert the weight | 10 × 0.45359237 | 4.5359 kg |
| 2. Raise to the 0.75 power | 4.53590.75 | 3.1081 |
| 3. Resting energy requirement | 70 × 3.1081 | 217.57 kcal |
| 4. Apply the factor | 217.57 × 1.2 | 261.08 → 261 kcal |
| 5. Calories to grams | 261 ÷ 400 × 100 | 65.25 g/day |
| 6. Divide by meals | 65.25 ÷ 2 | 32.625 g/meal |
| 7. Grams to scoops | 32.625 ÷ 12 | 2.72 scoops/meal |
| 8. Grams to cans | 65.25 ÷ 85 | 0.77 cans/day |
| 9. Days per bag | 3,000 ÷ 65.25 | 46.0 days |
Step 4 is the only rounding step, and everything after it uses the rounded 261. That is why the numbers above chain exactly: 261 ÷ 400 × 100 really is 65.25, and 65.25 ÷ 85 really is 0.768.
Calibrate your scoop once, then stop guessing
Nearly every feeding error on a dry-fed cat is a scoop error, not a calorie error. A scoop measures volume and food is sold by mass, so the two only agree if the food always packs the same way. A heaped scoop of one kibble can weigh half again as much as a level scoop of another.
- Put a bowl on a kitchen scale and press tare.
- Scoop ten level scoops into it, the way you normally scoop.
- Divide the reading by ten. That is s.
Ten scoops rather than one because a single scoop is worth a couple of grams of noise, and ten divides that noise by ten. Once you have s, the scoop line above is a real instruction instead of a guess.
Recalculates with the inputs above.
| Scoop weight | Scoops per meal | Scoops per day | Reads as |
|---|
The default scoop weight is 12 g, a common size for a dry cat food scoop. It is a starting point, not a fact about your scoop — weigh yours.
How long a pack actually lasts
This is the line that stops you running out mid-week. The daily gram figure divided into the pack, for the pack sizes people actually buy.
Recalculates with the inputs above; case sizes use the can weight you entered.
| Pack | Pack weight | Days it lasts | Packs per year |
|---|
Packs per year is 365 divided by days per pack, rounded up — the number you actually have to buy.
What this cat feeding calculator deliberately does not do
- It does not judge your cat's body condition. It uses the weight you type. Whether that weight is the right weight is a hands-on assessment, not an arithmetic one.
- It does not cover kittens, pregnancy, nursing, or illness. Growth, gestation, lactation and recovery all move the factor by more than the range on this page can absorb. Those need a veterinary plan.
- It does not subtract treats. The number is the main-food budget. Treats come out of it, not on top of it.
- It does not set a weight-loss target. A weight-loss portion is a different calculation with a different factor and a rate of loss attached. This page maintains.
- It does not choose a food, a brand, or a formula. Energy density is an input. Whatever is printed on your bag is the truth this page works from.
- It does not weigh your scoop for you. That takes a kitchen scale and ten scoops. The method is above; the number is yours.
Questions people ask this calculator
How many grams should I feed my cat per meal?
For the example cat — 10 lb, spayed, 400 kcal per 100 g, two meals — it is 32.6 g per meal, which is 2.72 level scoops at 12 g. Change any input above and both numbers move together, because the per-meal figure is just the daily figure divided by the meal count.
My scoop is not 12 grams. What do I do?
Put your own number in the scoop field. Nothing else on the page depends on the scoop weight — the grams per meal are fixed by body weight and food density, and the scoop line is only a translation of that into the thing you hold in your hand.
Two meals or three?
The daily total does not change. Two meals suits most adult cats; three or four is easier on a cat that eats fast, brings food back up after a big meal, or is being fed a large volume of a dilute wet food. Splitting more finely does not reduce calories, it only spreads them.
Can I use this for wet food only?
Yes, and the cans-per-day line is built for it. Enter the wet food's density in kcal per 100 g (the conversion from kcal per can is above) and the can's net weight. Expect a much larger gram figure than for dry food at the same calories, because wet food is mostly water.
Why is this different from the feeding guide on the bag?
Bag guides are written for a range of cats, rounded to convenient scoop counts, and they usually assume a more active cat than a neutered indoor one. They are a safe starting point, not a measurement of your cat. If your cat gains on the bag's suggestion, the bag is wrong for your cat — this arithmetic plus a weekly weigh-in will tell you by how much.
Do treats come out of this number?
Yes. The figure is the whole daily energy budget for food. A common working rule keeps treats and extras at or below a tenth of it, which for the example cat is about 26 kcal — taken out of the 261, not added to it.
My cat is overweight. Does this work?
Not for the weight-loss part. The maintenance factor on this page will hold an overweight cat at an overweight weight. Weight loss uses a lower factor, a target weight instead of a current weight, and a rate of loss that has to be supervised. Ask your veterinary team for that plan.
Where every number on this page comes from
- RER = 70 × kg0.75 — the standard resting energy equation used across veterinary nutrition, published by the Association for Pet Obesity Prevention and by university veterinary medical centres. Checked 2026-10-22.
- Factors 1.0 / 1.2 / 1.4 — the Association for Pet Obesity Prevention's cat feeding calculator publishes 1.0× for sedentary cats, 1.2–1.4× for typical spayed or neutered adults, and 1.4–1.6× for intact adults. This page uses the lower end of each range. Checked 2026-10-22. That is a single published source for the factors, and it is labelled as such rather than presented as a consensus.
- 1 lb = 0.45359237 kg and 1 oz = 28.349523125 g — exact definitions, not measurements.
- 1 kcal = 4.184 kJ — the thermochemical calorie definition, used for the kilojoule conversion above.
- Everything else — your cat's weight, your food's density, your can weight, your scoop weight, your pack size. There are no other constants on this page.
If a number here disagrees with your veterinary team's plan, their plan wins. This page is arithmetic, not a diagnosis.