A wig that's too big slides back by lunchtime. One that's too small pinches at the temples, lifts at the nape and leaves you with a headache by the end of the day, however good the hair looks. Both come from guessing. Measuring takes ten minutes.
Put your head circumference into the chart above, in inches or centimeters, and it lights your size on the full chart. If you're ordering a custom unit, open "Add more measurements" and enter the other five. The diagram shows where the tape goes for each one as you fill it in.
How to measure your head for a wig
Your size follows one number: the circumference round your hairline. Get that right and you're done.
Time: 10 min. What you need: Soft cloth tape measure, Mirror, Your usual wig cap, if you wear one.
- Braid it down firstCornrow or flatten your hair exactly the way it'll sit under the wig. Skip buns and ponytails, because they add inches the wig won't have.
- Use a soft tapeA cloth sewing tape bends round your head. No tape? Use a piece of string, mark where it meets, and lay it against a ruler.
- Measure the circumferenceStart at the middle of your front hairline. Follow the hairline behind one ear, round the nape of your neck, behind the other ear and back to the start. Keep it snug, not tight.
- Measure three timesTake it three times and use the number that comes up most. If one reading is way off, the tape slipped.
- Add the other five for a custom unitFront hairline to nape, ear to ear across the forehead, ear to ear over the top, temple to temple round the back, and nape width. Custom wig makers build the cap to these.
Measure on the hair you'll actually wear under the wig. It matters more than people think. A head braided down in cornrows can measure noticeably smaller than the same head with a puff on top, and that gap is the difference between two cap sizes.
What are the wig cap sizes?
Every published chart we read sizes wigs by head circumference first. The three middle sizes are where they agree, and the chart above has all six of their measurements in inches and centimeters.
Petite caps fit about 20 to 20.5 inches round. Some wig makers call this extra small, and a few use "petite" for what everyone else calls small, so check the inches, not the name.
Extra large caps fit about 24 to 24.5 inches round. Fewer wig makers stock them, and they rarely publish the other five measurements for petite or extra large.
Medium is the average cap. Most wigs are only made in medium. If your number lands at 22 to 22.5 inches, you're in luck: almost any wig off the shelf will fit.
What if you're between wig sizes?
No chart sets a cut-off in the gaps, at 21.5 to 22 inches or 22.5 to 23. We won't invent one. If you land there, the chart above shows both sizes and leaves the choice to you.
Most wig makers say to size up, then tighten the adjustable straps at the back. Those straps usually give about half an inch either way, which covers the whole gap. A few say your own hair should decide. Lots of hair under the cap means size up. Very short hair, a fine braid-down or no hair means the smaller size will sit flatter.
Combs and clips inside the cap help a slightly loose wig grip, and an elastic band does the same job on glueless units.
Braiding down flat under a wig
Get it as flat as you can. Straight-back cornrows are the usual base, small enough to lie flat at the crown and tucked in at the nape so nothing bulges under the cap.
Our braid size chart shows parting sizes from micro to jumbo, and for a braid-down you want the smaller end of it. Clean parts come from a rat-tail comb. An edge brush lays the hairline where the lace meets your skin.
At night, keep the braids under a satin bonnet so they stay neat for the next install. One customer told us about our bonnet:
"I don’t even need my big bonnet I had for box braids or wigs anymore! This is def a keeper!" Mimi
Wig length is measured from the crown
Not from your front hairline. So a wig sold at 16 inches falls longer than 16 inches of your own hair, because none of its length is spent travelling back over the top of your head the way your own hair's first few inches are.
Our hair length chart shows where each length lands on the body, ear to tailbone. Shopping for a wig? Go a little shorter than the landmark you want.
Frequently asked questions
Sources
The cap sizes, the six measurements, the between-size advice and the measuring steps come from thirteen published wig cap size charts and measuring guides, read October 11, 2026. The measurements for the three middle sizes are where three charts agree exactly. Petite and extra large circumferences come from the charts that list them. The review is from our own satin bonnet reviews.
Braid down, grab a soft tape, and put your number in the chart above.