# Pet Calorie Calculator

> Computes a dog's or cat's resting energy requirement (RER = 70 × kg^0.75) and multiplies it by the life-stage factor used by veterinary nutrition services (e.g. neutered adult dog 1.6, cat 1.2) to give daily maintenance calories.

- Calculator id: `pet-calories` · Category: Everyday Life (`everyday`) · Tool name: `calculate_pet_calorie_needs`
- Canonical page: https://tttkmbb.com/everyday/pet-calories · This document: https://tttkmbb.com/everyday/pet-calories.md · JSON definition: https://tttkmbb.com/everyday/pet-calories.json

## Purpose

Computes a dog's or cat's resting energy requirement (RER = 70 × kg^0.75) and multiplies it by the life-stage factor used by veterinary nutrition services (e.g. neutered adult dog 1.6, cat 1.2) to give daily maintenance calories.

**Use when:** You need a starting daily calorie target for a dog or cat from its weight and life stage, e.g. to portion food from the kcal/cup value on the bag.

**Do not use when:** The animal is pregnant, lactating, doing heavy work or is ill; those needs (2–8 × RER or disease-specific) require veterinary guidance. For people use tdee.

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `species` | enum: dog \| cat |  | required | Dog or cat; selects the factor table. |
| `weight_kg` | number | kg | required | Current body weight in kilograms (use the target weight for a weight-loss plan). (min 0.3, max 120) |
| `life_stage` | enum: neutered_adult \| intact_adult \| inactive_obese_prone \| weight_loss \| growth_under_4_months \| growth_4_months_to_adult \| light_work \| moderate_work |  | optional, default "neutered_adult" | Life stage or activity level; each maps to a multiple of RER. |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `rer_kcal_per_day` | number | kcal/day | RER = 70 × weight_kg^0.75. |
| `mer_factor` | number |  | Multiplier applied to RER. |
| `mer_kcal_per_day` | number | kcal/day | Maintenance energy requirement = RER × factor. |
| `mer_kj_per_day` | number | kJ/day | Same requirement in kilojoules (1 kcal = 4.184 kJ). |
| `weight_lb` | number | lb | Body weight in pounds. |

## Formula

`RER = 70 × weight_kg^0.75; MER = RER × factor (dog: neutered adult 1.6, intact 1.8, inactive 1.3, weight loss 1.0, puppy <4 months 3.0, puppy 4 months–adult 2.0, light work 2.0, moderate work 3.0; cat: neutered 1.2, intact 1.4, inactive 1.0, weight loss 0.8, kitten 2.5)`

Factors follow the Ohio State University Veterinary Medical Center table used with the WSAVA nutrition toolkit; the inactive dog factor is the midpoint of the published 1.2–1.4 range. The result is a starting point: weigh the animal every 2–4 weeks and adjust portions by about 10% to hold ideal body condition.

## Data Sources

- Ohio State University Veterinary Medical Center – Companion animal nutrition support service: basic calorie calculator — https://vmc.vet.osu.edu/services/companion-animal-nutrition-support-service (reference, retrieved 2026-09-24)
- WSAVA Global Nutrition Committee – Global nutrition guidelines and toolkit — https://wsava.org/global-guidelines/global-nutrition-guidelines/ (standard, retrieved 2026-09-24)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/pet-calories?species=…&weight_kg=…`
- `POST https://tttkmbb.com/api/v1/calculate/pet-calories` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/pet-calories · OpenAPI operationId `calculate_pet_calorie_needs` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "pet-calories", "inputs": {…}}`

## Example

- 10 kg neutered adult dog: inputs `{"species":"dog","weight_kg":10,"life_stage":"neutered_adult"}` → `{"rer_kcal_per_day":394,"mer_factor":1.6,"mer_kcal_per_day":630,"mer_kj_per_day":2635,"weight_lb":22}`
- 4 kg neutered adult cat: inputs `{"species":"cat","weight_kg":4,"life_stage":"neutered_adult"}` → `{"rer_kcal_per_day":198,"mer_factor":1.2,"mer_kcal_per_day":238}`

```
GET https://tttkmbb.com/api/v1/calculate/pet-calories?species=dog&weight_kg=10&life_stage=neutered_adult
```

## Limitations

The animal is pregnant, lactating, doing heavy work or is ill; those needs (2–8 × RER or disease-specific) require veterinary guidance. For people use tdee. Factors follow the Ohio State University Veterinary Medical Center table used with the WSAVA nutrition toolkit; the inactive dog factor is the midpoint of the published 1.2–1.4 range. The result is a starting point: weigh the animal every 2–4 weeks and adjust portions by about 10% to hold ideal body condition. All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**How do I turn calories into cups of food?**

Divide the daily calories by the kcal per cup (or per 100 g) printed on the food label; typical dry dog food is 300–400 kcal per cup.

**Why is the result lower than the feeding guide on the bag?**

Bag guides are often based on intact, active adults (1.8 × RER or more). Neutered, indoor pets need less, which is why many are overweight when fed by the bag.

## Related

- [Dog Age Calculator](https://tttkmbb.com/everyday/dog-age.md) — Life stage from the dog's age.
- [Cat Age Calculator](https://tttkmbb.com/everyday/cat-age.md) — Life stage from the cat's age.
- [TDEE Calculator](https://tttkmbb.com/health/tdee.md) — The equivalent calculation for people.