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PawCurve

Cat Calorie Calculator

Daily calories and portions, using the formula the current AAHA/AAFP feline guidelines actually publish — not the one every other calculator borrowed from somewhere else.

Use their ideal weight, not their current one, if those differ — your vet can tell you which.

Neutered?

Get this off your bag — it's the single biggest source of error here. Foods range from roughly 3,000 to 4,500 kcal/kg, so the default is a placeholder, not an answer. Wet food is far lower (often under 1,200).

Estimated daily energy

—kcal/day

≈ — of the food you entered

Resting requirement (RER)
—
Maintenance factor applied
—
Formula used
—

A story about how easy it is to invent a controversy

We checked the full guideline section because one sentence is easy to misread — and because we nearly made the same mistake ourselves. The guideline and textbook are not two competing authorities: one gives the clinical starting point, and the other quantifies common maintenance factors.

We found this sentence in the 2021 AAHA/AAFP feline guidelines: "needs factor, which in the case of young, healthy adults is 1". Meanwhile every cat calorie calculator on the web uses 1.2 or 1.4 — a 20% gap between the guideline's starting point and what most calculators show. That would have been a clean story, but it wouldn't have been the true one.

The full section resolves that difference:

  • The sentence was cut in half by a page break. Its real beginning sits at the bottom of the previous page: "A good starting point is to calculate the adult feline patient's resting energy requirements…" The "1" is where you start before adjusting — not a verdict. Reading only the second page gives you the opposite meaning.
  • The guideline cites the textbook. Reference 100 in that document is Hand's Small Animal Clinical Nutrition, 5th ed — the very book the 1.2/1.4 comes from. A source and the source it cites are not two warring authorities.
  • The formulas are different. The guideline's own linear formula gives 205 kcal for this example; the textbook uses an exponential form for its maintenance factors.

So the guideline gives the clinical flow, the textbook quantifies a step in it, and the calculator shows both as a starting range. We keep this trail visible because "we checked and we were wrong" is what makes "we checked and they were wrong" worth anything.

What the guidelines actually say

Here it is in full, so you don't have to take our word for it:

"A good starting point is to calculate the adult feline patient's resting energy requirements (RER) according to the following calculation: RER (kcal per day) = 30 × (body weight in kg) + 70. Daily energy requirements (DER) are determined based on multiplying by a needs factor, which in the case of young, healthy adults is 1."
— 2021 AAHA/AAFP Feline Life Stage Guidelines, pp. 13–14

And from the paragraph immediately before it:

"Energy requirements of cats are influenced by a variety of factors including age, BCS, MCS, neuter status, health status, and activity level… The amount fed should be adjusted to maintain or encourage ideal body condition, and a BCS should be documented by the veterinarian at each visit."

That's the whole model: a starting point, then adjust by what you see. The calculator above gives you both ends of the reasonable range — the guideline's start, and the textbook's maintenance estimate — because the practical output is a range you tune, not a number you obey.

Why there's no weight-loss setting

Cats that lose weight too fast can develop hepatic lipidosis, which is life-threatening. Weight-loss plans need a diagnosis, target, rate, and monitoring, so this calculator focuses on maintenance feeding for healthy cats.

Frequently asked questions

How many calories does my cat need?
The 2021 AAHA/AAFP Feline Life Stage Guidelines give a formula and a starting point: RER = 30 × weight(kg) + 70, and for a young healthy adult, daily energy = RER × 1. For a 4.5 kg cat that's about 205 kcal/day. Crucially, the guidelines call this "a good starting point" and say the amount "should be adjusted to maintain or encourage ideal body condition". It's where you begin, not where you stop.
Why is your number lower than other cat calorie calculators?
Because most of them apply a maintenance factor of 1.2 (neutered) or 1.4 (intact) on top, which lands around 246–287 kcal for the same 4.5 kg cat. Those factors come from Hand's Small Animal Clinical Nutrition, a textbook. They are one way of quantifying the "adjust to body condition" step the guideline describes. We show both, because the practical answer is a range you then tune, not a single figure.
So do the guidelines and the textbook disagree?
No. The AAHA/AAFP guideline cites that very textbook as one of its sources. They operate at different levels: the guideline gives the clinical flow (start at RER × 1, adjust by body condition), and the textbook quantifies one step of it. Read together, they point to a starting range rather than a conflict.
Why does the cat formula look different from the dog one?
Because we follow each species' own current guideline. The 2021 AAHA/AAFP feline guidelines publish the linear form, 30 × kg + 70 — we checked the whole document and "0.75" appears in it zero times. Cats weigh 2–8 kg, comfortably inside the 2–45 kg range the linear formula is stated for, so there's no cost to following it. Dogs span 1–90 kg, where the linear form breaks badly (17% high at 45 kg, 28% at 70 kg), so our dog food calculator uses the allometric form instead.
Does neutering change how much my cat should eat?
The guidelines list neuter status as one of the factors that influences energy needs, and note that neutering is a risk factor for obesity in cats, especially males — so dietary energy restriction may be appropriate to prevent weight gain. What they don't do is give a specific number for it. The textbook's 1.2 (neutered) versus 1.4 (intact) is where that number comes from. Use it as a nudge, and let the body condition score be the referee.
What about senior cats?
The guidelines address this and — unusually — the wording is ambiguous, so we'll quote rather than paraphrase: they say RER "will need to be multiplied by a factor of 10–20%, and in some cases as high as 25%". Taken literally, multiplying by 10–20% would mean feeding a fifth as much, which is obviously not the intent; they mean an increase of 10–20%. We're flagging that rather than silently "correcting" it, because a source that's unclear is something you should know about.
What's the biggest source of error here?
Not the formula — your food's energy density. Dry cat foods run roughly 3,500–4,500 kcal/kg and wet food is often under 1,200. If you use our 4,000 placeholder while your bag says 4,500, you're already 12% out before any formula runs. Read the bag, and weigh the food rather than scooping it.

Related

Sources last checked 2026-07-17. RER formula and the DER × 1 starting point: 2021 AAHA/AAFP Feline Life Stage Guidelines (verified by reading the full section, pp. 13–14, including a rendered check of the formula — that PDF's text layer garbles "=" and "+"). Maintenance factors: Hand's Small Animal Clinical Nutrition, 5th ed, Table 5-2 — a textbook, not peer-reviewed, and cited by the guideline above. Not from the NRC or WSAVA, contrary to common attribution. More on our methodology page.