Knowing your waist size is important, especially if you're shopping in vintage boutiques or looking to wear European clothing. Because pattern sizes vary across the globe, it's often more convenient to shop based on your measurements instead of inconsistently produced sizes. No matter what the garment's label says, you can determine whether it will fit by knowing your waist size and measuring the garment's waist.
Wear only your undergarments to take this measurement. If you measure over any clothing, even tight-fitting leggings, you won't get a true measurement.
Locate your natural waist. The natural waist is the narrowest part of your waist, usually found just above your belly button (See Reference 1).
Place the "zero" end of the tape measure in the centre of your waist and hold it with one hand.
Loop the tape measure around your waist until it touches the "zero" end.
Make sure you can slip one finger between the tape measure and your skin. Loosen the tape measure if you can't.
Note the measurement where the tape measure overlaps its "zero" end. This is your natural waist measurement.
Make another measurement about an inch below your belly button. Although this isn't your natural waist, it will come in handy for sizing low-rise trousers.
If you're having trouble finding your natural waist, put on a pair of pantyhose, leggings or other tight-fitting elastic-waist garment. Bend sideways to your left and then to your right. Let the elastic waist roll up or down naturally based on your movement. Wherever it settles is your natural waist. If you measured your waist using the centimetre side of a tape measure, divide the number by 2.54 to convert centimetres to inches. Carry a small tape measure with you when you shop and measure the waist of vintage clothing or European-sized clothing. You'll save the hassle of visually estimating the size of a garment or trying it on only to find out it doesn't fit.
Don't hold your breath or suck in your stomach when measuring your waist. This will only lead to an incorrect measurement. If you shop using the wrong measurement, clothes won't fit or hang properly on your figure.