# TDEE Calculator

> Estimates total daily energy expenditure from Mifflin-St Jeor BMR and an activity level, and derives calorie targets for maintaining, losing or gaining weight.

- Calculator id: `tdee` · Category: Health (`health`) · Tool name: `calculate_tdee`
- Canonical page: https://tttkmbb.com/health/tdee · This document: https://tttkmbb.com/health/tdee.md · JSON definition: https://tttkmbb.com/health/tdee.json

## Purpose

Estimates total daily energy expenditure from Mifflin-St Jeor BMR and an activity level, and derives calorie targets for maintaining, losing or gaining weight.

**Use when:** You need daily maintenance calories for an adult, or calorie targets for a mild/standard deficit or surplus.

**Do not use when:** The person is a child, pregnant or breastfeeding, or you only need the resting rate (use bmr).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `sex` | enum: male \| female |  | required | Biological sex used to select the formula coefficients. |
| `weight_kg` | number | kg | required | Body weight in kilograms. (> 0, max 700) |
| `height_cm` | number | cm | required | Height in centimetres. (min 50, max 300) |
| `age_years` | number | years | required | Age in years. (min 18, max 120) |
| `activity_level` | enum: sedentary \| light \| moderate \| very_active \| extra_active |  | optional, default "moderate" | Weekly exercise level; maps to the standard activity multipliers 1.2 / 1.375 / 1.55 / 1.725 / 1.9. |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `bmr_kcal_per_day` | number | kcal/day | Mifflin-St Jeor basal metabolic rate. |
| `activity_multiplier` | number |  | Factor applied to BMR. |
| `tdee_kcal_per_day` | number | kcal/day | Calories to maintain current weight. |
| `mild_loss_kcal_per_day` | number | kcal/day | Approximately 0.25 kg/week loss. |
| `loss_kcal_per_day` | number | kcal/day | Approximately 0.5 kg/week loss. |
| `mild_gain_kcal_per_day` | number | kcal/day | Approximately 0.25 kg/week gain. |
| `gain_kcal_per_day` | number | kcal/day | Approximately 0.5 kg/week gain. |

## Formula

`TDEE = BMR(Mifflin-St Jeor) × activity_multiplier; targets = TDEE ± 250 or ± 500 kcal/day`

## Data Sources

- Mifflin MD et al. (1990) A new predictive equation for resting energy expenditure, Am J Clin Nutr 51:241-247 — https://pubmed.ncbi.nlm.nih.gov/2305711/ (peer_reviewed, retrieved 2026-09-23)
- FAO/WHO/UNU (2004) Human energy requirements – physical activity levels — https://www.fao.org/4/y5686e/y5686e00.htm (standard, retrieved 2026-09-23)

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/tdee?sex=…&weight_kg=…&height_cm=…&age_years=…`
- `POST https://tttkmbb.com/api/v1/calculate/tdee` 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/tdee · OpenAPI operationId `calculate_tdee` 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: `calculate_tdee` (dedicated) or `run_calculator` with `{"calculator_id": "tdee", "inputs": {…}}`

## Example

- Male, 70 kg, 175 cm, 30 y, moderate: inputs `{"sex":"male","weight_kg":70,"height_cm":175,"age_years":30,"activity_level":"moderate"}` → `{"bmr_kcal_per_day":1649,"activity_multiplier":1.55,"tdee_kcal_per_day":2556,"loss_kcal_per_day":2056,"gain_kcal_per_day":3056}`

```
GET https://tttkmbb.com/api/v1/calculate/tdee?sex=male&weight_kg=70&height_cm=175&age_years=30&activity_level=moderate
```

## Limitations

The person is a child, pregnant or breastfeeding, or you only need the resting rate (use bmr). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**How accurate is TDEE?**

Typically within ±10–15%. Activity multipliers are coarse; track weight for 2–3 weeks and adjust intake by 100–200 kcal if weight moves unexpectedly.

**Which activity level should I choose?**

Count only deliberate exercise. Most office workers who train 3 times a week are 'light' or 'moderate', not 'very active'.

## Related

- [Macro Calculator](https://tttkmbb.com/health/macros.md) — Turn the chosen calorie target into macronutrient grams.
- [Calorie Deficit & Weight Loss Time Calculator](https://tttkmbb.com/health/calorie-deficit.md) — Estimate how long a deficit takes to reach a target weight.