Belt Size Converter
Belt sizes follow different conventions in the US and Europe. In the US, the standard convention is that a belt size equals your waist measurement in inches plus 2 (to allow the belt to fasten at the middle hole). In Europe, belt sizes are stated directly as the waist measurement in centimeters, often rounded to the nearest 5 cm. Enter your waist measurement and this calculator shows the recommended belt size in both systems.
Belt size formula
US belt size = waist (inches) + 2 | EU belt size = waist (cm), rounded to nearest 5
The conversion between inches and centimeters uses the exact NIST definition: 1 inch = 2.54 cm exactly. EU sizes are often offered in increments of 5 cm (80, 85, 90, 95, 100), so round to the nearest 5 for ordering.
Belt size reference table
- 28 in waist: US size 30, EU size 70 to 75 cm.
- 30 in waist: US size 32, EU size 75 to 80 cm.
- 32 in waist: US size 34, EU size 80 to 85 cm.
- 34 in waist: US size 36, EU size 85 to 90 cm.
- 36 in waist: US size 38, EU size 90 to 95 cm.
- 38 in waist: US size 40, EU size 95 to 100 cm.
Belt size converter: frequently asked questions
How is US belt size determined?
In the US, belt size typically equals waist measurement in inches plus 2 inches. A person with a 34-inch waist usually wears a size 36 belt. This allows the belt to fasten comfortably on the middle hole, leaving room to adjust tighter or looser.
How does EU belt sizing work?
EU belt sizes correspond directly to the waist measurement in centimeters. A 34-inch waist is approximately 86 cm, so the EU belt size would be 85 or 90 (rounded to the nearest 5). EU sizes go in increments of 5 cm in most brands.
Should I measure my waist or hips for a belt?
Measure the circumference where you actually wear your belt, which is typically at the natural waist for dress pants or lower (at the hips) for jeans. Use a flexible tape measure and measure over the shirt you would normally wear with the belt.
Why do belt sizes vary between brands?
Belts are not governed by a single mandatory standard. The +2 inches US rule is a convention, not a regulated standard. Some brands add 2 inches, others add 1 or 3. Always check the brand's specific size chart when ordering online.
What is the middle hole convention?
Most belts have 5 holes spaced 1 inch apart. The convention is that the center hole should be where you fasten the belt most of the time. This means buying a belt 2 inches larger than your waist lets you use the middle hole and adjust 2 holes in either direction.
Official sources
- NIST Handbook 44: Inch-to-centimeter exact definition.
- NIST SP 811: US customary unit conversion factors.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.