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Belt Size Calculator

Use this free belt size calculator to find the belt size that fits your waist. Enter your waist or pants size in inches or centimetres, choose men’s or women’s, and it gives your belt size in inches, centimetres, and the EU size sold in stores, plus the total belt length and where the buckle should sit. The rule behind it is simple: your belt size is your waist size plus 2 inches.

How it works

A belt is measured from the end of the buckle to the middle hole, and that length is the belt size. Your waist is smaller than that length because the belt has to wrap around you, pass through the buckle, and still reach a hole with some length left over for the tip. That is why the standard rule is to add 2 inches to your waist size: a 34-inch waist takes a 36-inch belt, a 30-inch waist takes a 32-inch belt, and a 40-inch waist takes a 42-inch belt. The extra 2 inches is not slack; it is the part of the belt that goes through the buckle and across to the middle hole.

The calculator starts from whatever you enter. If you enter inches, it adds the fit allowance directly: 2 inches for a standard fit, 1.5 inches if you like a snug belt, or 3 inches if you prefer a relaxed fit or wear thick layers underneath. If you enter centimetres, it first converts to inches by dividing by 2.54, adds the allowance, and then converts back, so the centimetre answer is exact rather than rounded at the start. It also gives the EU size, which is the belt length in centimetres rounded to the nearest 5, because that is how belts are labelled in most stores that use centimetres. A belt of 91.4 cm is sold as EU 90, and a belt of 96.5 cm is sold as EU 95.

Men’s and women’s belts follow the same rule, but the way sizes are sold differs. Men’s belts are usually sold by the belt size itself, so you can ask for a size 36 and get a belt that measures 36 inches to the middle hole. Women’s belts are often sold by dress size or by small, medium, and large, which makes the inch number even more useful: knowing your belt size in inches lets you check a size chart instead of guessing from a letter. This calculator gives the inch and centimetre numbers for both, so you can use whichever the store lists.

Your pants size is a good starting point, but it is not always your true waist size. Some brands cut their pants a little large or small, a practice known as vanity sizing, so a pair labelled 34 may actually measure 35 or 36 inches around the waistband. The most reliable number is a tape measurement taken where you actually wear your belt, which for most people is at the hips or just below the natural waist, over the trousers or jeans the belt will be worn with. Measure twice, standing relaxed, and use that number here.

A good fit means the belt fastens on the middle hole, usually the third of five holes. That leaves two holes on each side for days when you eat a big meal, wear a thicker sweater, or lose a little weight. If your belt only reaches the first hole, it is too short; if it reaches the last hole and the tip flaps past the first belt loop, it is too long. A belt that is one size too big is easy to live with, and a leather belt can be shortened by a cobbler, but a belt that is one size too small is rarely comfortable.

Common belt sizes

Worked example

A man wears size 34 pants and wants to order a belt online. His tape measurement confirms a 34-inch waist.

Step 1: Start with the waist — 34 inches.
Step 2: Add the standard allowance — 34 + 2 = 36 inches.
Step 3: Convert to centimetres — 36 × 2.54 = 91.4 cm.
Step 4: Round to the nearest EU size — 91.4 cm rounds to EU 90.

He should order a size 36 belt, or EU 90. Enter 34 inches in the calculator and it gives exactly that: belt size 36 in, 91.4 cm, EU 90. If his waist had been measured as 86 cm instead, the calculator converts 86 cm to 33.86 inches, adds 2 inches to get 35.86 inches, and converts back to 91.1 cm, which is again EU 90.

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