RER: Resting Energy Requirement
RER is the calories your cat needs at rest to breathe, circulate blood, maintain body temperature, and keep organs working. It is the foundation of feline calorie calculations.
RER = 70 x (weight kg)^0.75
Free Tool · Dry, Wet & Mixed Diets · Results in 30 Seconds
Cat Food Calculator: How Much Should I Feed My Cat?
Stop guessing at portion sizes. Enter your cat's details and get a precise daily food amount in grams, cups, and cans, plus a complete feeding schedule tailored to weight, age, and diet type.
Based on NRC & AAFCO feline standardsSupports dry, wet & mixed feedingIncludes weight loss & gain modes
Calculate Your Cat's Daily Food Portions
The Science
Understanding Your Cat's Daily Calorie Needs
The calculator converts weight into RER, then adjusts for life stage, neuter status, activity, and goal.
MER: Maintenance Energy Requirement
MER reflects real life needs. A neutered indoor adult may use 1.2x RER, while a growing kitten may need around 1.8-2.5x RER.
MER = RER x Life Stage Factor
Why Neutered Cats Need Less Food
Spaying and neutering commonly lowers energy needs and can increase appetite. Adjusting the MER factor helps prevent slow weight gain after surgery.
Neutered adult: about 1.2x RER
Diet Formats
Dry Food vs. Wet Food vs. Mixed: Which Is Right for Your Cat?
Dry Food Only
- ✓Convenient and affordable per calorie
- ✓Easy to measure and portion
- ✓Can work with puzzle feeders
- !Low moisture content
- !Easy to over-pour
- !Often less palatable
Best for: Cats with strong hydration habits and households that need convenient measured portions.
Wet Food Only
- ✓High moisture content
- ✓Closer to natural prey texture
- ✓Often higher protein
- !More expensive per calorie
- !Spoils within hours
- !Requires more frequent serving
Best for: Cats prone to urinary issues, senior cats, picky eaters, and cats needing hydration support.
Most Recommended
Mixed Feeding
- ✓Hydration from wet food
- ✓Convenience from dry food
- ✓More dietary variety
- !Requires calorie tracking
- !Both foods must be counted
- !Portions need a scale
Best for: Most indoor cats, especially neutered adults needing hydration plus enrichment.
Reference Table
Cat Feeding Guide by Weight and Life Stage
Reference portions for standard dry food at 350 kcal/100g. Adjust based on your specific food's calorie density.
| Body Weight | Kitten (6-12m) | Adult Neutered | Adult Intact | Senior (7+) |
|---|---|---|---|---|
| 2 kg | 61g (212) | 40g (141) | 54g (188) | 37g (129) |
| 3 kg | 82g (287) | 55g (191) | 73g (255) | 50g (176) |
| 4 kg | 102g (356) | 68g (238) | 91g (317) | 62g (218) |
| 4.5 kg | 111g (389) | 74g (260) | 99g (346) | 68g (238) |
| 5 kg | 120g (421) | 80g (281) | 107g (374) | 73g (257) |
| 6 kg | 138g (483) | 92g (322) | 123g (429) | 84g (295) |
| 7 kg | 155g (542) | 103g (361) | 138g (482) | 95g (331) |
| 8 kg | 171g (599) | 114g (400) | 152g (533) | 105g (366) |
All values are grams of standard dry food per day. For wet food, multiply by about 4.1x. Individual cats may need +/-20% adjustment.
Meal Timing
How Many Times a Day Should I Feed My Cat?
Kittens under 6 months
3-4 meals per day
Small stomachs, high energy needs, and blood sugar stability.
Example: 7am / 12pm / 5pm / 9pm
Adult Cats
2 meals per day
Mirrors a natural hunting pattern and supports healthy weight.
Example: 7am / 6pm
Senior Cats
2-3 meals per day
Smaller portions can support digestion and appetite.
Example: 7am / 1pm / 6pm
Free Feeding
Not recommended for most cats
Continuous grazing often leads to overeating and obesity.
Example: Dry food only, vet-guided
Related Tools
Complete Your Cat's Nutrition Picture
Cat Age Calculator
Convert cat years to human years using the feline-specific aging curve, not the outdated multiply-by-7 dog formula.
Cat Weight Calculator
Compare your cat's weight against breed-specific healthy ranges and get a Body Condition Score interpretation.
Cat Calorie Calculator
Get daily kcal targets using feline RER and MER formulas adjusted for spay status and activity level.
Feeding interpretation
Turn the portion result into a repeatable feeding routine
Food calculators are most helpful when they become a daily system: calories first, grams second, cups only as a rough fallback. This page helps translate weight, age, activity, food type, and weight goal into a portion that can be measured, tracked, and adjusted without guessing.
Result guide
How to read the daily portion
Start with the calorie target, then check the dry, wet, or mixed-food grams. A portion can look surprisingly small with calorie-dense dry food and much larger with wet food because water adds weight without adding many calories.
- Use grams when possible; cup measurements vary by kibble size and how tightly the cup is filled.
- Check the kcal per 100g or kcal per can on the actual label before relying on the default preset.
- For mixed feeding, confirm the dry/wet split describes calories, not the visual size of the bowl.
- Reassess after 3-4 weeks using weight trend and body condition, not one hungry-looking evening.
Calories explain most portion confusion
Two foods can have the same bowl volume but very different calorie density. The calculator keeps calories as the source of truth so grams and cups remain grounded.
Weight goals need ideal weight
For weight loss, portions should be based on a safe target or ideal weight, not simply a percentage of the current overweight body weight.
Meal timing matters
Splitting food into predictable meals can reduce begging, make appetite changes easier to notice, and support cats that eat too quickly.
Portion decisions
Choose the adjustment based on what changed
A feeding result is not a permanent prescription. It is a measured starting point that should move only when weight trend, body condition, food label, or life stage changes justify it.
Weight is stable
If body condition looks ideal and weight is steady, the result is doing its job. Avoid changing portions because of occasional begging or one missed meal.
Keep the same daily calories and review again after the next monthly weigh-in.
Weight is rising
A small upward trend usually means treats, dry-food density, free-feeding, or cup measurement error is pushing calories above the intended target.
Measure in grams for two weeks and subtract treat calories before lowering meals further.
Food brand changed
Switching foods can change calorie density enough to invalidate the old grams or cups even if the bowl looks identical.
Enter the new kcal per 100g, kcal per can, or kcal per cup before using the old routine.
Weekly during changes
Weigh weekly when changing portions, food type, or weight goals.
Monthly for maintenance
A monthly weight and body-condition check is enough for many stable adult cats.
Same-day recalculation
Recalculate immediately after a food-label, pregnancy, lactation, or target-weight change.
What to do after calculating
1
Weigh tomorrow's food once
Measure the full daily amount on a kitchen scale, then divide it into the meal schedule shown in the result.
2
Track body condition monthly
If weight drifts more than intended, adjust the total daily amount by about 5-10% and give the new routine time to show a trend.
3
Log treats separately
Treats, toppers, dental chews, and table scraps should come out of the daily calorie budget rather than sitting on top of it.
FAQ
Frequently Asked Questions About Cat Feeding
How much should I feed my cat per day?
Most adult neutered indoor cats need between 180-250 calories per day, depending on their weight and activity level. A typical 4.5kg neutered indoor cat needs approximately 218 kcal/day, which is about 62g of standard dry food or about 210g of wet food per day.
How much wet food should I feed my cat per day?
For a typical 4.5kg adult neutered cat, approximately 210-250g of standard wet food per day, or about 1.3-1.6 standard 156g cans. Always check your specific food's calorie density.
How much dry food should I feed my cat per day?
For a typical 4.5kg adult neutered cat, approximately 60-70g of standard dry food per day, roughly one third cup using a standard measuring cup. Weighing food is more accurate than cup measurements.
How much should I feed an overweight cat?
For weight loss, reduce daily calories to the cat's RER calculated at ideal body weight, not current weight. Never reduce calories by more than 25% at once because rapid weight loss can cause hepatic lipidosis.
Should I feed my cat dry food or wet food?
Both formats can support a healthy cat when total calories are appropriate. Wet food provides more hydration, while dry food is convenient. Many cats do well with a carefully measured mixed approach.
How often should I feed my cat?
Most adult cats do well with 2 meals per day, spaced 8-12 hours apart. Kittens under 6 months need 3-4 smaller meals daily, and senior cats may benefit from 2-3 smaller meals.
Why does my cat seem hungry even after eating the right amount?
Neutering, boredom, fast eating, and opportunistic feeding behavior can all make cats seem hungry after adequate meals. Puzzle feeders and monthly weight tracking can help distinguish behavior from true calorie need.
How do I know if I'm feeding my cat the right amount?
Track body condition score and monthly weight trends. If weight changes by more than 1-2% per month without intention, adjust portions by about 10% and reassess after 4 weeks.