Measuring in inches or centimetres: getting it right either way

Reading the tape

• Check which side you are reading. Most soft tapes have inches on one side and centimetres on the other. Choose a side before you start and keep it facing out.
• Start at zero. Some tapes have a metal tip or a short blank section before the first mark. Line up the zero mark itself.
• Read fractions carefully. Inch tapes are usually marked in halves, quarters and eighths; write 34½ or 34.5 rather than “34 and a bit”. Centimetre tapes are marked in millimetres or half centimetres, and 87.5 cm is perfectly fine.
• Round to the nearest half. Half an inch or half a centimetre is precise enough; there is no need for more decimal places.
• Write each number down straight away, with its unit, before moving on to the next measurement.
• Use a tape in good condition. Old fabric tapes can stretch, so compare yours against a ruler if it has seen years of use.
• Keep the tape level and snug, not tight. Ease is added when the outfit is cut, not when you measure.

Converting, if you must

The easiest option is not to convert at all: choose the unit you measured in on the form. If you do need to convert, the rule is exact: 1 inch is 2.54 centimetres. Multiply inches by 2.54 to get centimetres, or divide centimetres by 2.54 to get inches.

• 36 inches is 91.4 cm.
• 40 inches is 101.6 cm.
• 15 inches is 38.1 cm.
• 64 inches (5 ft 4 in) is 162.6 cm.
• 100 cm is 39.4 inches.

Mixed units and other traps

Convert each measurement from the original number, not from a rounded one, and avoid shortcuts such as “2.5 cm to the inch”: over a 40 inch hip, that shortcut loses 1.6 cm.

• Height in feet and inches: if you enter your height alongside your other measurements, it goes in the same unit as the rest, so 5 ft 4 in becomes 64 inches (not 54) or 162.6 cm.
• Measurements from a garment: if you measure a kameez lying flat, the width across the front is only half the full measurement. Say it is a flat measurement rather than doubling it yourself. See using a kameez that fits as a template.
• Brand size charts: Pakistani and Indian size charts sometimes give garment measurements rather than body measurements, and some mix units. Treat them as a guide, not as your measurements. See brand size charts vs made to measure.
• Old notebooks: if you are reusing measurements from a tailor abroad, check which unit they used; a 36 written years ago could be inches or a size.

Check your numbers before you send

A quick sense check catches most mistakes. Your bust, waist and hip numbers should all look like the same kind of number: if your bust says 36 and your hips say 102, one of them is in the wrong unit. Measure twice, and if the two readings differ, measure a third time.

Your key measurements are checked with you before cutting, so flag anything you are unsure of in the notes. Our guide to common measuring mistakes covers the rest, and the custom stitching service explains how the fit is built from your numbers.