Cat Calorie Calculator
How Many Calories Does My Cat Need?
Get your cat’s daily calorie target in seconds. Based on their weight, life stage, and body condition — not a generic chart.
How Many Calories Should a Cat Eat Per Day?
Three quick inputs. We’ll give you the number, explain what it means, and tell you exactly how many treats your cat can have without going over.
The formula used here is the same one veterinary nutritionists use in clinical practice:
RER (Resting Energy Requirement) is the calories your cat needs just to keep their body running — breathing, circulation, temperature, organ function. It’s calculated as 70 × (weight in kg)^0.75, which is the exponential formula validated by the American College of Veterinary Nutrition and endorsed by the WSAVA.
MER (Maintenance Energy Requirement) is RER multiplied by a life stage factor. Neutered adults get ×1.2 because reproductive hormones affect metabolic rate. Kittens get ×1.9 to support rapid growth. The body condition adjustment modifies the target: slim cats eat slightly above maintenance to build condition, overweight cats eat at or below RER to encourage safe fat loss.
Cat Calorie Chart — Daily kcal by Weight and Life Stage
A quick-reference calorie chart for cats. All figures use the RER formula (70 × kg^0.75) with life stage multipliers. For your cat’s specific number, use the calculator above.
Cat Daily Calorie Needs — by Weight
RER formula · WSAVA standard| Cat weight | RER (resting) | Neutered adult ×1.2 | Intact adult ×1.4 | Senior ×1.1 | Weight loss ×0.8 |
|---|---|---|---|---|---|
| 2 kg / 4.4 lb | 118 | 141 | 165 | 129 | 94 |
| 2.5 kg / 5.5 lb | 140 | 168 | 196 | 154 | 112 |
| 3 kg / 6.6 lb | 160 | 192 | 224 | 176 | 128 |
| 3.5 kg / 7.7 lb | 179 | 215 | 251 | 197 | 143 |
| 4.5 kg / 10 lb ★ | 214 | 257 | 299 | 235 | 171 |
| 5 kg / 11 lb | 234 | 280 | 327 | 257 | 187 |
| 5.5 kg / 12 lb | 252 | 302 | 352 | 277 | 202 |
| 6 kg / 13.2 lb | 269 | 323 | 377 | 296 | 215 |
| 7 kg / 15.4 lb | 304 | 365 | 426 | 335 | 243 |
| 8 kg / 17.6 lb | 337 | 404 | 472 | 371 | 270 |
Life Stage Multipliers — How Cat Calorie Needs Change
| Life stage | Multiplier | Why this number? |
|---|---|---|
| Kitten under 4 months | ×2.5 | Rapid organ and skeletal development — the highest calorie need relative to size in a cat’s life |
| Kitten 4–12 months | ×1.6–2.0 | Still growing fast. Closer to 2.0 at 4 months, tapering to 1.6 toward one year |
| Neutered adult (most common) | ×1.2 | Neutering reduces metabolic rate by roughly 20–30%. The most frequently cited multiplier in practice. |
| Intact adult | ×1.4 | Reproductive hormones keep metabolism slightly higher. Intact females in oestrus may need more. |
| Senior (10+ years) | ×1.1 | Activity naturally declines. But protein needs increase to maintain muscle — don’t cut protein to save calories. |
| Pregnant queen | ×1.6 | Gradually increase through gestation. By late pregnancy, some queens need up to 1.25× normal food intake per week. |
| Nursing (peak lactation) | ×2.0–4.0 | The highest demand of an adult cat’s life. Often best managed by free-feeding kitten food during this period. |
| Safe weight loss | ×0.8 RER | Feed at 80% of RER. This is the safe deficit — enough to lose 0.5–1% body weight per week without risking fatty liver. |
Why the food label amount is often wrong
The 30% rule — why estimates vary
How Many Calories Does a Cat Need Per Day?
There’s no single number that works for every cat. A 3 kg kitten and a 6 kg neutered adult live in very different metabolic states — and their calorie needs reflect that. The RER formula gives you a personalised figure based on your cat’s actual biology.
The starting point is the RER — Resting Energy Requirement. This is the number of calories your cat needs just to exist: to breathe, circulate blood, regulate temperature, and keep their organs running. At rest, a typical 4.5 kg neutered cat needs around 214 kcal per day just to stay alive.
But cats don’t just rest. They play, groom, move around, and — if they’re a kitten — they also grow. The MER (Maintenance Energy Requirement) accounts for this by multiplying RER by a life stage factor. A neutered adult gets ×1.2, pushing the 4.5 kg cat’s need to around 257 kcal per day. A kitten might get ×2.0 or higher, reflecting the enormous energy cost of growing from a tiny handful of fur into a full-grown cat in under twelve months.
What throws people off is that the number on the cat food bag is not this calculation. Pet food feeding guides are written for a hypothetical average cat and tend to run generous. Following them closely without adjusting for whether your cat is neutered, how active they are, or their current body condition is one of the most common reasons cats become overweight.
Understanding Your Cat’s Body Condition Score
Body condition score (BCS) is the tool vets use to judge whether a cat is at a healthy weight — and it’s something you can assess at home. The key is using your hands, not just your eyes. Cats with thick fur can look fine while being significantly underweight or overweight.
About 60% of domestic cats are overweight or obese in the UK and US, making excess weight the most common nutritional problem in cats. The health consequences are significant: overweight cats have a higher risk of diabetes, joint disease, urinary problems, certain cancers, and a shorter lifespan. Even moving from a BCS of 7 to a BCS of 5 can meaningfully improve a cat’s health and longevity.
Calories for Cat Weight Loss — How to Do It Safely
Weight loss in cats requires more care than in most other animals. Cats are the only species known to develop hepatic lipidosis (fatty liver disease) from calorie restriction that is too aggressive — so getting the deficit right actually matters.
| Step | What to do | Why it matters |
|---|---|---|
| 1. Set the target | Feed at 80% of RER (not MER). This is the safe deficit for cats. | Going below RER risks triggering hepatic lipidosis — even in a short period of restricted eating. |
| 2. Set the rate | Aim for 0.5 to 1% of body weight loss per week. For a 6 kg cat, that’s 30 to 60 grams per week. | Faster than this increases fatty liver risk significantly. Slower is fine and often safer. |
| 3. Use wet food | Wet food is lower in calorie density and higher in water. It helps cats feel fuller on fewer calories. | Many cats tolerate a calorie deficit better on wet food than the same deficit from dry kibble. |
| 4. Weigh regularly | Weigh your cat every 2 weeks using accurate scales (10g precision). | Small changes are easy to miss otherwise. If no loss after 4 weeks, reduce by a further 10%. |
| 5. Never crash-diet | Do not withhold food or skip meals entirely to speed things up. | Even 24 to 48 hours without eating can trigger lipidosis in an overweight cat, especially if stressed. |
Making the Calorie Count Actually Work Day to Day
Knowing the right calorie number is only half the job. The other half is measuring and feeding it consistently. Most overfeeding happens not because owners don’t know the target, but because portions drift over time.
Cat Calorie Calculator — Questions and Answers
Common questions about how many calories cats need, the RER formula, weight loss, treats, and why the food bag number is usually wrong.
It depends on your cat’s weight, life stage, and whether they are neutered. For a neutered adult cat, the daily calorie needs work out approximately as follows:
- 3 kg (6.6 lb) cat — about 192 kcal per day
- 4.5 kg (10 lb) cat — about 257 kcal per day
- 6 kg (13.2 lb) cat — about 323 kcal per day
Kittens need significantly more — up to double the adult amount relative to their weight. Senior cats need slightly less. These figures come from the RER formula (70 × weight in kg^0.75) multiplied by a life stage factor. The calculator above applies this automatically and gives you the result for your cat specifically.
RER stands for Resting Energy Requirement — the calories a cat needs just to keep their body running while completely at rest. It covers breathing, circulation, organ function, and temperature regulation. The formula is RER = 70 × (weight in kg)^0.75.
It’s used because it’s validated by veterinary research and endorsed by the WSAVA (World Small Animal Veterinary Association) and the American College of Veterinary Nutrition as the standard for calculating feline energy needs. It takes into account that larger animals don’t need proportionally more calories — metabolic rate scales with body surface area, not body mass.
The calculator is almost certainly more accurate for your individual cat. Pet food feeding guides are written for a hypothetical average cat — they don’t account for whether your cat is neutered, how active they are, or their current body condition.
Research has found that following label feeding guidelines results in overfeeding by 20 to 50% in neutered indoor cats. One 2010 study published in the Journal of the American Veterinary Medical Association found that commercially available diet foods frequently provided more calories than recommended for weight loss when the label guidelines were followed.
Start with the calculated amount. Weigh your cat every 4 to 6 weeks. If their weight is stable, the amount is right. If gaining, reduce by 10 to 15%.
The most reliable way is the rib check. Run your fingers along your cat’s ribcage without pressing hard. At an ideal weight, you should be able to feel individual ribs easily — like knuckles under a thin layer of skin — but not see them. If you have to press firmly to feel ribs, your cat is likely overweight. If ribs are visible, they’re too thin.
From above, a cat at ideal weight has a visible waist — a narrowing between the ribcage and hips. An overweight cat looks more oval from above, with no visible waist. A very overweight cat may have a pendulous belly visible from the side.
Don’t rely on appearance alone, especially for longhaired breeds — a Persian at a healthy weight can look quite fluffy and round. The rib feel is the most reliable home check.
The safe approach is to feed at 80% of RER — not 80% of the maintenance amount. This creates a gentle calorie deficit while keeping you well above the threshold that risks hepatic lipidosis (fatty liver disease).
For example, a 6 kg overweight cat has an RER of around 269 kcal. Feeding at 80% of RER means roughly 215 kcal per day. At this level, the target rate of weight loss is 0.5 to 1% of body weight per week — for a 6 kg cat, that’s about 30 to 60 grams per week.
Never cut calories abruptly or skip meals entirely to speed up weight loss in a cat. Even 24 to 48 hours without eating can trigger hepatic lipidosis in an overweight cat — it’s a serious and potentially fatal condition that occurs when the body mobilises fat for energy faster than the liver can process it.
Unexplained weight loss in a cat — especially a senior cat — is always worth a vet visit. It’s one of the most common presentations of serious underlying conditions. The most frequent causes include:
- Hyperthyroidism — very common in cats over 10. The thyroid produces too much hormone, raising metabolism dramatically. Cats eat more but still lose weight.
- Chronic kidney disease (CKD) — also very common in older cats. Poor appetite and reduced ability to use nutrients leads to muscle wasting.
- Diabetes mellitus — elevated blood glucose means the body can’t use glucose for energy properly, so it burns muscle and fat instead.
- Inflammatory bowel disease or intestinal lymphoma — affects nutrient absorption.
- Dental disease — pain when eating reduces intake gradually and owners often don’t notice until significant weight loss has occurred.
A basic blood panel and urinalysis at the vet can identify most of these conditions. Treating the underlying cause usually stabilises weight better than just increasing calories.
Treats should make up no more than 10% of your cat’s total daily calories. For a neutered 4.5 kg cat on 257 kcal per day, that’s about 26 kcal worth of treats. Temptations-style treats contain around 2 kcal each, so that’s roughly 13 treats per day — if you reduce meals by the same amount.
The key word there is “if you reduce meals.” The 10% treat rule only works if you subtract treat calories from the food portion. Giving full meals plus treats on top is where the calories add up quickly. A cat getting 15 treats a day on top of full meals is eating 30 extra kcal per day — which adds up to a meaningful excess over time.
Yes — and this is well established in veterinary research. A 1997 study by Fettman et al. found that neutering reduces resting metabolic rate in cats by approximately 20 to 30%. This is why the MER multiplier for neutered adults is 1.2 rather than the 1.4 used for intact cats.
In practical terms, it means a neutered cat eating the same amount as before being neutered will gradually gain weight — often starting within a few months of the procedure. This is the most common trigger for adult cat obesity. Adjusting portions at or around the time of neutering (or shortly after) is the most effective prevention.
Many vets now recommend discussing post-neuter calorie needs at the time of the surgery appointment, rather than waiting until the cat has already gained significant weight.
Yes. Select “Growing kitten” in the calculator and enter your kitten’s current weight. The calculator applies the appropriate multiplier for kittens (×1.9, which sits in the middle of the recommended 1.6–2.5 range for kittens under 12 months).
A few things to note for kittens: their calorie needs change rapidly as they grow, so recalculate every 4 to 6 weeks. Most vets recommend feeding kittens kitten-formula food rather than adult food — it’s higher in protein and fat, which supports proper development. And unlike adult cats on weight management, kittens should generally not have their calories restricted — underfeeding during growth causes lasting developmental issues.
Calculate your cat’s exact calorie needs
Use the calculator above. Enter weight, life stage, and body condition — and get the daily target, treat budget, and weight loss plan if needed.