# Units (cm and inches)

> The API always uses millimetres and kilograms. The measuring window and the fit view show centimetres or inches by the shopper's country and language, and the shopper can switch.

Source: https://docs.tryyoursize.com/guides/units/

## The API: millimetres and kilograms

Every value you send or receive is metric, whatever the shopper sees:

- girths, lengths, ease and height in **millimetres** (`value_mm`, `height_mm`, `ease_mm`);
- weight in **kilograms** (`weight_kg`);
- pressure in **kPa**.

You never convert. A shopper who types 32 in is stored as 812.8 mm, and 812.8 mm shows as 32 in again.

## What shoppers see

The measuring window, the fit view and the shopper's account show measurements in one of three settings:

| Setting | Girths and lengths | Height | Weight |
|---|---|---|---|
| Metric | cm | cm | kg |
| Imperial | in | ft + in | lb |
| Imperial with stone | in | ft + in | st + lb |

The default comes from the shopper's country and language region:

- **United States**: imperial.
- **United Kingdom**: inches for girths and lengths, ft + in for height and st + lb for weight, because UK clothing is labelled in inches and people commonly give their weight in stone. Pounds and metric are one tap away.
- **Everywhere else**: metric.

The shopper can switch on every measuring screen. The choice is saved to their TryYourSize profile when they are signed in, so it follows them to every store, and is also remembered in the browser.

Numbers use the language's decimal mark: `72,5 cm` in Spanish, French, German and Italian; `72.5 cm` in English. Fit numbers ("1.2 in of room") follow the same setting; pressure always reads in kPa.

When a value looks like it was typed in the other unit (32 in a centimetre field for a waist, or 81 in an inch field), the window asks before it uses it.

## Brands: specs in inches or centimetres

In Studio, each garment's specs can be entered and shown in centimetres or in inches with fractions to 1/8 in (`32 1/4`, `32¼`, `32.25` and `32-1/4` all work). Spec-sheet imports detect inch columns; when a sheet does not say, Studio asks which unit it uses. The stored values are the same millimetres either way, so switching the display never changes a spec.