Pet food calculator
Daily food ration from body weight, requirement multiplier and food energy.
Fill in the fields and the result will appear here automatically.
Converts a selected energy estimate into food grams using its energy density. The starting resting energy requirement, RER = 70 × weight^0.75, appears in AAHA guidance for initial calculations; it does not measure an individual animal’s expenditure. The multiplier is entered by the user. Species, age, neutering and body condition are not separate inputs that choose a ration automatically. Energy density must describe the food actually offered. Treats and other energy sources need separate accounting.
How it works
Formula and logic
RER kcal/day = 70 × kg^0.75. Estimated energy = RER × entered multiplier; food g/day = energy ÷ kcal per 100 g × 100. Weight, multiplier and energy density must be positive. This is a starting estimate to monitor and adjust, not an established individual requirement.
Example
Entered weight 22 kg, multiplier 1.6 and 350 kcal/100 g give about 325 g/day. These are illustrative inputs, not a ration prescribed for every 22 kg dog. Doubling entered density to 700 kcal/100 g halves grams in the same model while estimated energy stays unchanged.
Fields and units
- Body weight, kg — kg
- Energy requirement multiplier — unitless
- Food energy, kcal per 100 g — kcal/100 g
How to use
- — Check weight and the calculation’s aim against an assessment of body condition.
- — Enter an appropriate agreed multiplier; activity does not select it automatically.
- — Use the particular food’s kcal/100 g and account for other energy sources.
- — Monitor weight and body condition; the calculated grams may need individual adjustment.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- AAHA 2021: RER 70 × weight^0.75 and starting factors with monitoring and individual adjustment; not a prescribed ration
- Limitation
- An initial estimate cannot replace individual veterinary feeding advice, especially during growth, illness, pregnancy or weight reduction.
FAQ
Why the power of 0.75 rather than plain weight?
The power 0.75 belongs to an approximate RER equation. It does not prove that any two animals need food in that exact ratio: species, life stage and condition also matter.
Which multiplier should I use?
The factor depends on more than activity. AAHA gives starting ranges such as 1.2–1.4 for neutered cats and 1.4–1.6 for neutered dogs, with individual monitoring and adjustment. This tool does not choose them automatically.
Should I feed the target weight or the current one?
It depends on the aim. AAHA discusses ideal weight for weight reduction; selecting weight and feeding strategy requires the animal’s condition. This field does not determine a target weight.
Does wet food change the calculation?
The equation is unchanged, but use the particular wet food’s energy density. Lower kcal/100 g requires more mass for the same estimated energy; no universal wet-food density is assumed.