# Belt Size Calculator

URL: https://speedycalculator.com/calculators/everyday-life/belt-size/
Last updated: 2026-10-25

> The belt size calculator finds your belt size in inches and centimetres and the letter size (S to 4XL) from your waist measurement, trouser size or a belt you already own.

## Inputs

- I know my
- Measurement (in, cm)

## Results

- Belt size
- European size (cm)
- Letter size
- Approximate overall belt length

## Formula

```
Belt size = trouser waist size + 2 in (5 cm)
Belt size from an old belt = length from the buckle fold to the hole you use
Total belt length ≈ belt size + 5–6 in for the buckle and tip
```

## Explanation

Belt sizes are measured from where the leather folds at the buckle to the middle hole, so a belt labelled 36 fits a 34 in trouser waist with room to adjust either way. Measuring a belt that already fits is the most reliable method.

### How to use the Belt Size Calculator

- **I know my**
- **Measurement**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Choose what you know – your waist circumference, your trouser size or the length of a belt that fits – and enter it.

### Belt size chart

Trouser waistBelt sizeLetter28–30 in30–32XS30–32 in32–34S34–36 in36–38M38–40 in40–42L42–44 in44–46XL46–48 in48–502XL

### Tips

- Measure over thin clothing with a soft tape held snug but not tight, and keep the tape level all the way round.
- Take each measurement twice; if you are between sizes, the larger size is usually the safer choice.
- Size charts vary by brand and country – check the maker's own chart when it is available.
- For sewing projects, pre-wash fabric before cutting and buy 10% extra for shrinkage, pattern matching and mistakes.

### Common mistakes to avoid

- Mixing inches and centimetres between the tape and the size chart.
- Forgetting seam and hem allowances when cutting fabric.
- Measuring an old, stretched garment instead of your body.

### Inputs explained

FieldWhat to enterI know myChoose one: Waist circumference (measured), Trouser / jeans waist size, Old belt: buckle fold to the hole I useMeasurementUnits: in, cm

### What each result means

- **European size (cm)** = round([Belt size]÷0.05)×5
- **Approximate overall belt length** = [Belt size] + 5.5×0.0254

## Worked example

Inputs — I know my: Trouser / jeans waist size; Measurement: 34 in.

Results — **Belt size = 36 in**; European size (cm) = 90; Letter size = M; Approximate overall belt length = 41 in.

## FAQ

**What size belt for 34 waist jeans?**
A size 36 belt.

**How do I measure a belt?**
Measure from the fold where the buckle attaches to the hole you use most.

**What if I am between sizes?**
Choose the larger size – you can always use a tighter hole.

**What formula does the Belt Size Calculator use?**
Belt size = trouser waist size + 2 in (5 cm).