---
title: "Body Fat Percentage Calculator (Navy Method)"
method: POST
path: "/api/v1/tools/body-fat-calculator"
tags: ["fitness"]
---

# Body Fat Percentage Calculator (Navy Method)

`POST /api/v1/tools/body-fat-calculator`

## Request

- Base URL: `https://calcfleet.com`
- URL: `https://calcfleet.com/api/v1/tools/body-fat-calculator`
- Auth: none declared

Estimate your body fat percentage with the US Navy tape-measure method. Enter your sex, height, neck, waist, and hip to see body fat and lean body mass.

## Request body

- object
  - `sex` 'male' | 'female', required
  - `waistCm` number, required
  - `neckCm` number, required
  - `hipCm` number
  - `heightCm` number, required
  - `weightKg` number

## Response `200`

Successful calculation result.

- object
  - `result` object, required: Structured calculation output (fields vary per calculator).

## Other responses

- `400`: Invalid input — the issues array contains Zod validation errors.
- `403`: Forbidden — an Authorization: Bearer cf_… key was supplied but is invalid.
- `404`: Unknown tool slug.

---

[API](https://skmtc.dev/calcfleet/apis/calcfleet-financial-calculators-api.md) · [All operations](https://skmtc.dev/calcfleet/apis/calcfleet-financial-calculators-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calcfleet/apis/calcfleet-financial-calculators-api/revisions/cd9abd595bbe?raw)