Body Fat Calculator
body_fat_calculatorRead-onlyIdempotent
A body fat calculator that works from a tape measure, using the US Navy method. A HelpySelf tool (helpyself.com).
Tool call template
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"sex": "<sex>",
"height": "<height>",
"neck": "<neck>",
"waist": "<waist>"
},
"name": "body_fat_calculator"
}
}Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| hip | No | Hip circumference at the widest point, in the unit named by system. Required when sex is female; ignored when male. | |
| sex | Yes | Which of the two US Navy equations to use; they are not interchangeable. female needs a hip measurement and uses waist plus hip; male uses the waist alone. | |
| neck | Yes | Neck circumference measured just below the larynx, in the unit named by system. Must be smaller than the waist (or waist plus hip for female) or the request is refused. | |
| waist | Yes | Waist circumference, relaxed, in the unit named by system: at the navel for men, at the narrowest point for women. | |
| height | Yes | Standing height, in the unit named by system. | |
| system | No | The unit every measurement is in. metric (the default) reads height, neck, waist and hip in centimetres and weight in kilograms; imperial reads lengths in inches and weight in pounds. | metric |
| weight | No | Body weight in kg (metric) or lb (imperial). Not part of the percentage; it is only used to also return fat mass and lean mass in the same unit. Omit it and those come back null. |