Methodology

Last updated: November 3, 2026

Our calculators use the widely published resting and daily energy requirement formulas found in public veterinary references such as the WSAVA Global Nutrition Guidelines and the Merck Veterinary Manual. All results are estimates only and are not a substitute for advice from your veterinarian.

All calculators at a glance

Every tool uses the same two-step method — RER, then a life-stage multiplier — and differs only in the multipliers offered:

• Dog food calculator — adult dogs, ×1.2 to ×3.0 by activity.
• Puppy food calculator — ×3.0 under 4 months, ×2.0 from 4–12 months.
• Senior dog calculator — ×1.2 to ×1.4.
• Cat food calculator — adult cats, ×1.0 to ×1.6 by activity.
• Kitten food calculator — ×2.5 up to 12 months.
• Senior cat calculator — ×1.1 to ×1.2.
• Dog and cat feeding-by-weight guides — ranges from the lowest to an active adult multiplier.

All results are estimates based on standard formulas, not veterinary advice.

1. Resting Energy Requirement (RER)

RER (kcal/day) = 70 × (body weight in kg)^0.75

Weights entered in pounds are converted using 1 kg = 2.20462 lb.

2. Daily Energy Requirement (DER)

DER = RER × life-stage factor

Factors marked Verified match commonly cited values in public veterinary sources. Factors marked Preliminary are reasonable mid-range values where published ranges are wide; treat them with extra caution.

3. Converting to cups

Cups per day = DER ÷ kcal per cup

Calorie density varies widely between foods, so enter the "kcal/cup" value printed on your food's label. Default values in the calculators are placeholders only. Preliminary

4. Example calculations

50 lb spayed/neutered adult dog (food at 350 kcal/cup):

• 50 ÷ 2.20462 = 22.7 kg
• RER = 70 × 22.7^0.75 ≈ 727 kcal/day
• DER = 727 × 1.6 ≈ 1163 kcal/day
• Cups = 1163 ÷ 350 ≈ 3.32 cups/day

10 lb spayed/neutered adult cat (food at 400 kcal/cup):

• 10 ÷ 2.20462 = 4.5 kg
• RER = 70 × 4.5^0.75 ≈ 218 kcal/day
• DER = 218 × 1.2 ≈ 262 kcal/day
• Cups = 262 ÷ 400 ≈ 0.66 cups/day

20 lb senior dog with low activity (food at 350 kcal/cup):

• 20 ÷ 2.20462 = 9.1 kg
• RER = 70 × 9.1^0.75 ≈ 366 kcal/day
• DER = 366 × 1.2 ≈ 439 kcal/day
• Cups = 439 ÷ 350 ≈ 1.25 cups/day

10 lb adult cat with low activity (food at 400 kcal/cup):

• 10 ÷ 2.20462 = 4.5 kg
• RER = 70 × 4.5^0.75 ≈ 218 kcal/day
• DER = 218 × 1.0 ≈ 218 kcal/day
• Cups = 218 ÷ 400 ≈ 0.55 cups/day

These examples are estimates only; your pet's actual needs may be higher or lower.

Limitations

• Individual energy needs can differ from formula estimates by 20–30% or more.
• Formulas do not account for medical conditions, pregnancy, lactation or breed-specific needs.
• Treats and extras add calories not included in the cup estimate.
• Monitor body condition and weight, and adjust with your veterinarian.

Weight-range guides

The dog feeding by weight and cat feeding by weight pages apply the same RER formula at common adult weights. Each range runs from a low-activity factor (dogs ×1.2, cats ×1.0) to an active factor (dogs ×2.0, cats ×1.6). Like every figure on this site, these are estimates only, not veterinary advice.

Senior calculators

The senior dog and senior cat calculators use the same RER/DER formulas with the lower senior factors from the table above (dogs ×1.2–1.4, cats ×1.1–1.2). Older pets usually burn less energy, but published senior ranges are wide, so these results are estimates only — treat them as a starting point and adjust with your veterinarian.

Try the dog, cat, puppy or kitten calculator. See also our FAQ and disclaimer.