Belt Size Calculator
Belt length from your trouser waist.
Work out belt size from your trouser waist or a measured waistline, with the total strap length and where the middle hole should fall.
Your trouser size, or a measured waistline — but not interchangeably, since trouser labels often run small.
Belt size
36
91 cm · strap about 39 in
Belts are sized to the middle hole, not the tip, which is why a belt marked 36 measures nearer 39 overall. Two inches above the trouser waist puts the prong in the middle hole with a shirt tucked in.
How the Belt Size Calculator works
A belt is sized to the hole you use, not to the strap. The convention is two inches above your trouser waist, which puts the buckle prong in the middle hole with the belt worn over trousers and a shirt tucked in. Sizing to your actual waist measurement is the usual mistake, and it leaves the belt one hole short.
Also known as: belt length chart · waist to belt size
Why belt size is not waist size
A belt is measured from the fold at the buckle to the middle hole, not to the tip of the strap. The middle hole is the design fit, with two holes of adjustment in each direction. That is the number printed on the belt.
The convention is that the belt size sits two inches above the trouser waist, because a belt is worn over trousers and a tucked shirt rather than against the skin. Sizing a belt to a measured waistline puts the prong at the first hole with nothing in reserve.
That is why a belt marked 36 measures nearer 39 inches overall. The tail beyond the middle hole is not part of the stated size, which surprises people who measure a belt end to end and conclude it is mislabelled.
A worked example
A 34-inch trouser waist takes a 36 belt. The prong sits in the middle of five holes, leaving roughly two inches of adjustment in each direction, and the total strap runs to about 39 inches with a tail long enough to pass through the keeper.
If you measured your actual waistline rather than reading a trouser label, use that figure plus two instead. Trouser sizes are frequently vanity-sized an inch or two below the real measurement, so adding two to a label that is already two inches optimistic produces a belt that is four inches short of comfortable.
Where the answer misleads
Where you wear the belt changes the measurement. A belt worn on the hips with low-rise trousers needs a larger size than the same person wearing it at the natural waist, and the difference can be two full sizes. The trouser waist figure assumes the belt sits where the trousers do.
Thick fabrics eat length. A belt worn over a heavy shirt, a waistcoat, or chunky winter trousers needs more than one worn over a thin shirt, which is why a belt that is comfortable in summer can be on its last hole in January.
If you are between sizes, buy the larger. Leather belts with removable buckles can be trimmed and re-punched by any cobbler in a few minutes, which is a normal alteration; a belt that is too short cannot be fixed at all.
Frequently asked questions
What size belt should I buy?
Two inches above your trouser waist size. A 34 waist takes a 36 belt, which puts the prong in the middle of five holes and leaves room in both directions.
Should I measure my waist or use my trouser size?
Either, but not interchangeably. Trouser sizes are often vanity-sized an inch or two below the real measurement, so if you measure your waistline directly, use that number plus two rather than your label size plus two.
How is belt length actually measured?
From the fold at the buckle to the middle hole, not to the tip. That is why a belt marked 36 has a total strap length nearer 39 inches — the tail past the middle hole is not counted.
What if I am between sizes?
Take the larger and, if it is a leather belt with a removable buckle, have the tail trimmed and re-punched. That is a normal alteration and cheaper than a belt that sits on the last hole from day one.