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Dog Food Portion Calculator

Q: Where do I find kcal per cup?

On the bag's guaranteed analysis or feeding guide as 'ME (calculated) kcal/cup' or kcal/kg; divide kcal/kg by 10 to get kcal per 100 g.

Q: Why is this less than the bag's feeding chart?

Feeding charts are typically based on intact, active adults (1.8 × RER or more); most neutered pets need 20–30 % less, which is why bag-fed dogs often gain weight.

Q: Do treats count?

Yes: keep treats under 10 % of daily calories and reduce the food portion accordingly, otherwise the diet becomes unbalanced and the dog overeats.

Estimates a dog's resting energy requirement (RER = 70 × kg^0.75), multiplies it by the life-stage factor used by veterinary nutrition services (e.g. neutered adult 1.6, puppy under 4 months 3.0) and converts the daily calories into cups and grams of a food of known energy density, with a meal split.

When to use

You need to know how many cups or grams of a specific food to feed a dog per day from its weight, life stage and the kcal per cup or per 100 g on the bag.

Do not use when: The dog is ill, underweight, a giant-breed puppy or on a prescription diet; results are informational starting points, not veterinary advice. For cats or a calorie figure without food conversion use pet-calories.

Formula

RER = 70 × weight_kg^0.75; MER = RER × factor (puppy <4 months 3.0, puppy 4–12 months 2.0, neutered adult 1.6, intact adult 1.8, inactive 1.4, weight loss 1.0, senior 1.4, moderate work 3.0, last-trimester pregnancy 3.0, lactation 4.0); cups_per_day = MER / food_kcal_per_cup; grams_per_day = MER / food_kcal_per_100g × 100

Factors follow the Ohio State University Veterinary Medical Center calorie table used with the WSAVA nutrition toolkit; the inactive factor is the upper end of its 1.2–1.4 range, the senior factor 1.4 and the lactation factor the lower bound of 4–8. Individual needs vary by ±25 %, so the portion is a starting point to be adjusted against body condition; informational, not veterinary advice.

Inputs

Parameter	Type	Unit	Required	Description
`weight_kg`	number	kg	yes	Current body weight (use the target weight for weight loss). Range: ≥ 0.5, ≤ 120
`life_stage`	enum: puppy_under_4_months \| puppy_4_to_12_months \| adult_neutered \| adult_intact \| adult_inactive_obese_prone \| weight_loss \| senior \| working_dog_moderate \| pregnant_last_trimester \| lactating		default adult_neutered	Life stage or activity; each maps to a multiple of RER.
`food_kcal_per_cup`	number	kcal/cup	default 350	Metabolisable energy per standard 8 oz measuring cup from the bag (dry foods 300–450). Range: ≥ 50, ≤ 1000
`food_kcal_per_100g`	number	kcal/100 g	no	Energy per 100 g from the bag, to get the portion in grams (dry foods 330–420, wet foods 70–130). Range: ≥ 30, ≤ 700

Outputs

Output	Type	Unit	Description
`rer_kcal`	number	kcal/day	RER = 70 × weight_kg^0.75.
`mer_factor`	number		Multiplier applied to RER.
`mer_kcal`	number	kcal/day	Maintenance energy requirement = RER × factor.
`cups_per_day`	number	cups	mer_kcal / food_kcal_per_cup.
`grams_per_day`	number	g	mer_kcal / food_kcal_per_100g × 100 (when given).
`meals_per_day`	integer		2 for adults, 3 for puppies of 4–12 months, 4 for puppies under 4 months.
`cups_per_meal`	number	cups	cups_per_day / meals_per_day.
`grams_per_meal`	number	g	grams_per_day / meals_per_day (when given).
`meals_note`	string		How to split the daily amount.
`body_condition_note`	string		How to adjust the portion over time.

Example

20 kg neutered adult, 350 kcal/cup: {"weight_kg":20,"life_stage":"adult_neutered","food_kcal_per_cup":350} → {"rer_kcal":662,"mer_factor":1.6,"mer_kcal":1059.2,"cups_per_day":3.03,"meals_per_day":2,"cups_per_meal":1.51}

5 kg puppy of 6 months, 380 kcal/cup, 360 kcal/100 g: {"weight_kg":5,"life_stage":"puppy_4_to_12_months","food_kcal_per_cup":380,"food_kcal_per_100g":360} → {"rer_kcal":234.1,"mer_kcal":468.1,"cups_per_day":1.23,"grams_per_day":130,"meals_per_day":3,"grams_per_meal":43}

GET https://tttkmbb.com/api/v1/calculate/dog-food-portion?weight_kg=20&life_stage=adult_neutered&food_kcal_per_cup=350

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/dog-food-portion (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/dog-food-portion · Markdown: https://tttkmbb.com/everyday/dog-food-portion.md · JSON definition: https://tttkmbb.com/everyday/dog-food-portion.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="dog-food-portion"
OpenAPI operationId: estimate_dog_food_portion
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

Where do I find kcal per cup?

On the bag's guaranteed analysis or feeding guide as 'ME (calculated) kcal/cup' or kcal/kg; divide kcal/kg by 10 to get kcal per 100 g.

Why is this less than the bag's feeding chart?

Feeding charts are typically based on intact, active adults (1.8 × RER or more); most neutered pets need 20–30 % less, which is why bag-fed dogs often gain weight.

Do treats count?

Yes: keep treats under 10 % of daily calories and reduce the food portion accordingly, otherwise the diet becomes unbalanced and the dog overeats.

Related calculators

Pet Calorie Calculator — Calorie needs for dogs and cats without food conversion.
Dog Age Calculator — Life stage from the dog's age and size.