How many calories should my cat eat per day?

Daily calories depend on body weight, activity, and whether the goal is weight loss, maintenance, or gain. This tool estimates kcal using RER × activity/goal multipliers.

How do I convert calories to grams of cat food?

Divide required kcal by your food’s energy density (kcal per kg) and multiply by 1000 to get grams per day. For example, 220 kcal/day ÷ 3800 kcal/kg × 1000 ≈ 58 g/day.

Is wet or dry food better for weight loss?

Either can work with accurate portions and veterinary guidance. Wet food often has lower kcal per gram, which can help some cats feel fuller at similar calories.

Should I change portions if my cat is very active?

Active cats typically need higher multipliers. Monitor body condition score (BCS) and adjust with your vet’s help.

How often should I recalculate portions?

Recheck every 2–4 weeks during weight changes, and any time you switch brands or your cat’s activity or environment changes.

Is this veterinary advice?

No. This is an educational estimate. Your veterinarian should confirm calorie targets and monitor health factors like BCS and muscle mass.

Cat Calorie & Portion Size Calculator

About Cat Calories, RER, and Portion Sizes

Setting the right daily calorie target is the foundation of healthy feline nutrition. This calculator estimates your cat’s daily energy intake using the Resting Energy Requirement (RER) and then applies practical multipliers to reflect activity level and weight goals. RER is commonly approximated as 70 × (body weight in kg)^0.75. From there, a more active cat or one that needs to gain weight will typically require a higher multiplier than a sedentary cat or one on a weight‑loss plan. Because every cat’s metabolism is unique, it’s essential to track body condition score (BCS), muscle condition, appetite, and behavior and to re‑evaluate your plan with your veterinarian.

Translating calories into grams depends on your specific food’s energy density. Dry foods often range around 3600–4200 kcal/kg, while many wet foods fall near 700–1200 kcal/kg, but labels vary widely. To convert calories to grams, divide the daily kcal by the food’s kcal per kilogram, then multiply by 1000. If your cat needs 220 kcal/day and your dry food provides 3800 kcal/kg, your portion is roughly 220 ÷ 3800 × 1000 ≈ 58 g/day. If you feed multiple meals, split this daily gram amount into consistent portions to keep hunger and weight stable.

For weight loss, consistency and gentle calorie deficits are key—rapid changes can be unsafe. Aim to recheck weight every 2–4 weeks, adjust portions gradually, and combine feeding plans with enrichment, puzzle feeders, and vet‑approved activity to support lean mass. Conversely, for underweight cats or those regaining muscle, you may step calories upward while tracking stool quality, energy, and BCS. Senior cats, brachycephalic breeds, and cats with medical conditions (e.g., CKD, diabetes, GI sensitivities) require individualized guidance; your veterinarian may recommend specific therapeutic diets or supplementation. Always introduce new foods slowly to protect digestive comfort and avoid aversion.

Finally, hydration matters. If your cat prefers dry food, consider adding water or partial wet meals to increase moisture intake—especially important in hot climates or in cats with urinary issues. Use a digital kitchen scale for precise portions and record feedings during transitions. With a thoughtful, data‑driven approach and regular veterinary check‑ins, you can fine‑tune calories and portions to maintain a healthy weight, shiny coat, and playful energy for years to come.