How to measure pants and jeans flat: rise, thigh, leg opening

Measured flat, a pair of pants gives nine numbers. Two of them, the waist and the hips, decide the size. The others describe the cut: how high the waistband sits (rise), how much room the leg has (thigh, knee), how it ends (leg opening) and how long it is (inseam, outseam). Merchants publish them as garment measurements; shoppers can take the same numbers from a pair that fits and compare.

How to measure pants laid flat, step by step

You need a flat table and a tape measure or a long ruler.

1. Button, zip and lay flat, front up, legs together. Smooth the fabric with your hands without pulling it. Stretch denim measures larger stretched.
2. Waist. Straight across the top of the waistband, edge to edge. That's half the waist. On an elastic waistband, measure it relaxed.
3. Hips. Straight across the widest part, usually around the bottom of the fly. Also a half. Some brands call it the seat.
4. Front rise. From the crotch seam, where the four seams meet, up along the front seam to the top of the waistband.
5. Back rise. The same at the back: turn the pants over and measure from the crotch seam up the back seam to the top of the waistband.
6. Thigh. Straight across one leg just below the crotch, at a right angle to the leg. A half.
7. Knee. Straight across the leg halfway down the inseam, or at the point your own specs use. A half.
8. Leg opening. Straight across the hem, edge to edge. A half.
9. Inseam. From the crotch seam to the bottom of the hem, along the inside seam.
10. Outseam. From the top of the waistband straight down the side seam to the hem.

Measure the same points on every size, and two pieces per size if you can. Wherever you measure the thigh and the knee, write it down and keep it for the whole range.

What each number tells a shopper

The rise is why two pairs with the same waist number fit differently: a high rise closes around the natural waist, a low rise around the hips, where most bodies are wider. Thigh and leg opening have their own glossary entries, and the inside and outside lengths are in how to measure inseam.

An example chart, laid flat

Here is an example chart for this article, a pair of chinos in inches. Every width is laid flat:

Doubled, a size 32 measures 33 in at the waist, 42 in at the hips, 25 in around the thigh and 15.5 in around the hem. The rise and the inseam are lengths: they're never doubled.

Common mistakes

• Measuring unbuttoned. An open fly lets the waistband spread.
• Rise to the bottom of the waistband. It runs to the top edge.
• A slanted thigh line, or a different distance below the crotch on each size.
• Pulling stretch denim flat until it's bigger than it is.
• Doubling the rise or the inseam. Only widths double.
• A cuffed hem left rolled when you measure the leg opening or the inseam.
• Halves and circumferences in one table. Pick one for every row, and say which in the header.

What it means for a Shopify store

• Waist and hips choose the size; the rest describes the cut. Body measurements can go in one tab and these garment measurements in another, as several Ruban Size templates do for tops and jackets.
• Say "laid flat" in every header that holds a half.
• Name the cut in a fit note, for example "Slim through the thigh". The Men's pants template's note: "Slim cut: if you are between sizes, take the next size up."
• One unit per chart, with a switch for the other. Pant sizes are inches; many shoppers outside the US measure in centimeters.

How Ruban Size reads pants laid flat

Halves. Header words such as "flat", "laid", "half" or "width" mark a half, which Find my size doubles. Values count too: on an adult chart, a waist under 52 cm (20.5 in) or hips under 68 cm (26.8 in) can't be a body, so they're read as laid flat even without the word. A header Ruban can't read, such as "Seat", isn't taken as the hips on its own: click the line's label in the editor and choose Hips.

Room. Then it adds ease for the type of pants and the fit the shopper picked, in centimeters around the body. Jeans are recognized by the words "jeans" or "denim":

The pants hip values are the midpoints of the Vogue, Butterick and McCall's allowances for skirts and pants (2 to 3, 3⅛ to 4 and 4⅛ to 6 in), the waist values follow the 1 to 1.5 in minimum of Threads #221 (2023), and jeans sit one step closer.

A worked example. On the chinos chart, a shopper with a 32 in waist and 38.5 in hips, Regular fit. Waist: 32 in plus 3.2 cm (1.26 in) is 33.26 in, against the 33 in of a size 32. Hips: 38.5 in plus 9 cm (3.54 in) is 42.04 in, against 42 in. The answer is "Your size: 32", with "Waist 32 in: 32, middle of the range", "Hips 38.5 in: 32, middle of the range" and "Inseam 32 in: the same for every size", then "This chart gives the garment's own measurements: we added room for the fit you chose." With "Fit I like: Loose", the hips move up: "You are between 32 and 34. We suggest 34." Call the same chart "Slim jeans" and the closer jeans ease applies: Regular still gives 32, Snug reads "You are between 30 and 32. We suggest 32."

The cut lines. Rise, thigh, knee and leg opening aren't measurements Find my size uses. Mark those rows as "Other values" ("Converted when it has a unit; not used by 'Find my size'"): they switch between cm and in with the table, and shoppers compare them with a pair they own. The Men's pants template starts the other way round, with body measurements in inches and the line "Measurements are body measurements, in inches."; add a garment tab next to it for the cut.

Questions

How do you measure the rise on pants?

Lay them flat and buttoned, and measure from the crotch seam, where the four seams meet, along the front seam to the top of the waistband. Do the same at the back for the back rise.

How do you measure the thigh of jeans laid flat?

Straight across one leg, just below the crotch, at a right angle to the leg. Double it for the thigh all round.

What is the leg opening on pants?

The width of the hem, measured straight across the bottom of the leg laid flat. Doubled, it's the circumference of the hem: small for skinny cuts, large for bootcut and wide legs.

Do you double the waist of pants measured flat?

Yes. The flat waist is half the waistband; double it to compare with a waist measured around the body, and expect the pants to be a little larger than the body they fit.