How to measure your chest, and the three mistakes people make

The chest is the single most important number on a suit order, and the one people most often get wrong by an inch or more. An inch matters.

Taking it

• Wear a thin shirt or a fitted T-shirt. Not bare, not a jumper.
• Put the tape around the fullest part of your chest, which is usually right across the nipples and under the arms.
• Bring it round to the front and read where it meets, keeping it level all the way round.
• Arms down and relaxed. Breathe normally, then read the number on a normal breath out.

The three mistakes

Holding your breath in. People stand taller and pull their chest up the moment a tape goes round them. You are measuring the body that will wear the suit on an ordinary day, not the body in a photograph. Let your shoulders drop.

Letting the tape sag at the back. The tape goes round your back too, and without a helper it drifts downward where you can't see it. That adds length and gives you a bigger number than you are. A mirror, or a second pair of hands, fixes it.

Adding room. Do not add an inch "for comfort". Tell us your body, and we add the right amount of ease for the fit you picked. If you add some too, your jacket ends up loose and nobody can tell whether the number or the cut was at fault.

Snug, not tight. You should be able to slide a finger under the tape, and no more.

If the number surprises you

Most men guess their chest a size low, because they remember the jacket size they wore at twenty-five. Trust the tape. If your measurement doesn't match the jacket size you usually buy, that is information, not a mistake — and it is exactly why a suit cut to your measurements fits better than the one you have been putting up with.