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url: /docs/api/core/functions/zoneToPercentFtp.md
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[**@kaiord/core**](../README.md)

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[@kaiord/core](../README.md) / zoneToPercentFtp

# Function: zoneToPercentFtp()

> **zoneToPercentFtp**(`zone`): `number`

Defined in: [packages/core/src/domain/zones/power-zones.ts:51](https://github.com/pablo-albaladejo/kaiord/blob/3eacbe62ef72342d970523967cc5155b5935bb85/packages/core/src/domain/zones/power-zones.ts#L51)

Map a Coggan power zone (1..7) to its percent-FTP value.

## Parameters

### zone

`number`

## Returns

`number`

## Throws

RangeError when `zone` is not an integer in the closed interval \[1, 7].
The contract is strict: `0`, `8`, `-1`, `NaN`, `Infinity`, and
non-integers like `1.5` are all rejected. The helper MUST NOT
return `undefined`, `null`, or a silently clamped value.