Ask five people how to measure your waist and you'll get five places for the tape. The belly button. The top of the hip bone. The narrowest part. Over your jeans. Wherever it lands. Each spot can give a different number, so learning how to measure waist size mostly comes down to picking one spot and sticking with it.
Skip that step and a size that should be simple turns into a guess, then a box going back to the store. If that's been you, you're far from alone. Sizing and fit are the biggest reason online clothes go back: about 70 percent of online apparel returns in the 12 months the research covered, according to Coresight Research and Alvanon, as Sourcing Journal reported in May 2026.
So here's the plan, paso a paso. One spot, one method, one number you can repeat. Then we'll show you how to read that number for everyday clothes and for a waist trainer.
First, find your natural waist
Your natural waist is the narrowest part of your middle, usually above your hip bones and below your ribs. Fitting guides keep it simple, and so will we: measure the smallest part of the waist, as New Mexico State University's Cooperative Extension puts it in its guide to fitting pants.
Once you find it, tie a ribbon snugly around that spot and leave it there while you take your other measurements. That's the guide's own tip, and it means you never have to hunt for the spot twice.
Not sure which spot is the narrowest? Take the tape around your middle at two or three heights, an inch or so apart, and go with the smallest number. Everything after this step depends on it, so it's worth two extra minutes.
How to measure your waist, step by step
You don't need special gear. A soft tape measure, a mirror and two minutes are enough.
- Stand tall and relaxed, in front of a mirror. Bare skin or one thin layer is best. No jeans, no thick top.
- Wrap the tape around your natural waist. Keep it flat and level all the way around, parallel to the floor. Check the mirror, because the back of the tape can drift lower without you noticing.
- Keep it snug, not squeezing. The tape should lie against your skin without pressing into it.
- Breathe out normally, then read the number. Take the reading at the end of that normal breath out. Don't hold your breath and don't pull in.
- Measure twice. If the two numbers don't match, measure a third time and write down the one that repeats.
The tape technique here is the one the CDC's 2021 measuring manual lays out for its survey staff, trimmed down for your bathroom mirror. Their staff check the tape in a mirror so it stays level, keep it snug without pressing into the skin, and read the number at the end of a normal breath out. They also have a second person check the tape from the other side, so if you can, grab a friend and let them look at yours.
No tape? Use a string or a ribbon
No soft tape at home? A piece of string, a ribbon or a shoelace works fine.
Hold it around your natural waist and follow the same steps: level, snug, a normal breath out. Pinch the spot where the end meets the rest, or mark it with a pen. Then lay the string out straight, without stretching it, along a ruler or a yardstick and read the length.
A strip of paper works the same way. Wrap it, crease it where the end meets the rest, then flatten it and measure from the end to the crease.
Do it twice here too. Then write down the number and the unit you used, inches or centimeters, so you never have to wonder later.
The mistakes that change your number
None of these is a personal failing. They're small technique slips, and each one moves your number.
- Pulling in or holding your breath. Take the reading at the end of a normal breath out instead.
- A tilted tape. When the back of the tape dips, it measures a longer path around you than a level tape does, so the number usually creeps up. Let the mirror catch it.
- Pulling too tight. A tape that presses into the skin usually reads smaller than one that lies snug. Snug is the goal. Pinching is not.
- Measuring over clothes. Jeans and thick tops add fabric to the loop, and that fabric turns into inches that aren't yours.
- Measuring the wrong spot. The belly button and the top of the hip bone aren't your natural waist, and each one can give a different number.
- Rounding to the number you were hoping for. Write down exactly what the tape shows, as close as you can read it, and let the size chart do the deciding.
Even the pros don't all pick the same spot. The CDC manual marks its measuring site just above the top of the hip bone, while the New Mexico State guide says the smallest part of the waist. Try it yourself in a minute. Measure at your belly button, at the top of your hip bone and at your natural waist, and write all three numbers down. Those gaps are exactly why the spot matters, and why it pays to pick one and keep to it every time.
Using your number when you shop for clothes
Your number is a starting point. Every brand draws its own size lines, so the chart on the page you're shopping decides your size, not the label on your last pair. Blame the system, not yourself: the same research points to sizing that's inconsistent and fit standards that are fragmented.
Sewers have a trick you can borrow. They take three measurements, bust, waist at the natural waistline and hips, and match them to the size chart. New Mexico State's Cooperative Extension calls accurate measurements essential to that match, in a guide revised in January 2015. A store's size chart follows the same idea.
So write your number down with the date and the unit, and compare it with each brand's own chart before you order. A single note on your phone does the job. When you measure your bust or hips later, add them to the same note.
Measuring for pants and jeans is a separate question. So is measuring bust, waist and hips together, which is what dresses and bodysuits ask for.
Reading your number for a waist trainer
If you're shopping for a waist trainer, your waist number does the most work, because our chart runs on waist measurement. Our own sizing advice calls that spot your natural waist, the narrowest part of your midsection, so that's the number to bring here. Here's the chart for the All-Day Waist Trainer (Black), in inches, as it appears on its product page:
| Size | Waist measurement (inches) |
|---|---|
| XXS | 20-22 |
| XS | 22-24 |
| S | 24-26 |
| M | 26-28 |
| L | 28-30 |
| XL | 30-32 |
| 2XL | 32-34 |
| 3XL | 34-36 |
| 4XL | 36-38 |
| 5XL | 38-40 |
| 6XL | 40-42 |
Find your number in the right-hand column and read across to your size. If you measure 27 inches, for example, your number falls inside the M range, 26 to 28. Read the unit at the top of the chart before you compare, because a number in centimeters will land in the wrong size if you read it against the inches.
Notice that neighboring sizes share an end number. XXS runs 20 to 22 and XS runs 22 to 24, for example.
So what if your number lands right on one of those shared numbers, or somewhere between two sizes? Our waist trainers run small, so we recommend going one size above what you'd normally wear. If you're between sizes or just starting out, size up.
Waist size is one number. Torso length is another. Our Plus Size All-Day 14” Long Torso Waist Trainer (Black) comes in sizes XL to 4XL and reaches lower than our standard-length trainers. It's designed for longer torsos, or for anyone who prefers a little more coverage, which is why your torso length is worth knowing before you choose.
Quick answers about measuring your waist
Where exactly is your natural waist?
It's the narrowest part of your middle, what New Mexico State's fitting guide calls the smallest part of the waist and what our own sizing advice calls the narrowest part of your midsection. As a general guide, that's usually above your hip bones and below your ribs, but the smallest point on your body is the one to trust. Tie a ribbon or a piece of string snugly around that spot so you can find it again while you take your other measurements.
Should you measure your waist over clothes or on bare skin?
Bare skin or one thin, close layer works best. Anything thicker adds bulk under the tape, and the number grows with it.
Do you breathe in or out when you measure your waist?
Breathe out normally, then read the number at the end of that breath. That's how the CDC's measuring manual does it: the reading is taken at the end of a normal breath out. Don't hold your breath and don't pull in.
Is your waist size the same as your pants size?
Not always. Brands set their own size lines, so the same waist number can land in a different size from one brand to the next. Compare your number with the size chart of the exact brand you're buying, and measure separately for pants and jeans.
Should you measure in inches or centimeters?
Either one works, as long as you stay in one unit and match it to the chart you're reading. The size chart on our All-Day Waist Trainer page lets you switch between inches and centimeters.
How do you measure your waist for a waist trainer?
Use the same method as above: natural waist, bare skin or one thin layer, tape level and snug, read at the end of a normal breath out. Then find your number on the size chart of the style you want. The All-Day chart is above. For any other style, check the size chart on its product page.
How often should you re-measure your waist?
Before every new order. Brands size differently, so a number that matched one chart can land somewhere else on the next. It takes two minutes, and it's a lot easier than a return.
Measure once, write it down, and order with confidence, a tu medida. When you're ready for a waist trainer, start with our waist trainer collection.