An outseam measurement is the length of the outside of a trouser leg, taken from the waistband straight down to the hem. It is the longer of the two lengths a pair of trousers has, and the one you meet most often on shorts.
The inseam is its opposite number, running down the inside of the leg from the crotch to the same hem. Both end in the same place. They start in different ones, and that is the whole difference.
The definition, precisely
Take a pair of trousers and lay them flat. The outer edge of the leg runs unbroken from the waistband to the hem, usually with a seam along it. The length of that edge is the outseam.
It includes the rise, meaning everything between the waistband and the crotch. The inseam does not. So on any given pair, the outseam is always the larger figure, by the depth of the rise.
Some brands call it the outside leg, the side seam length, or simply the length. On Amaji product charts it appears as length.
Outseam and inseam, side by side
- Outseam. Waistband to hem, down the outside. Includes the rise. Describes how much leg the garment covers.
- Inseam. Crotch to hem, down the inside. Excludes the rise. Describes where the hem lands relative to your leg.
- The gap between them. The rise, typically 25 cm to 32 cm on trousers and 28 cm to 30 cm on shorts.
Neither is better. They answer different questions, and a chart that gives you only one is asking you to work out the other.
Why some brands publish one and not the other
It is largely a regional habit. American denim grew up on waist and inseam, which is why a label reads 32 x 34. Much of the rest of the market measures the garment flat and reports its total length.
That convention shows up clearly in our own catalogue. Every product page carries the manufacturer's own flat measurement chart, transcribed and converted to centimetres. Across the 98 charts on the site, the word inseam does not appear once, and all 22 charts covering bottoms give an outside length instead.
So if a number looks impossibly large, it is almost certainly an outseam. A 102 cm figure on the Quick-Dry Cargo Joggers at size S is an outside length. As an inseam it would fit nobody.
Shorts are sold on outseam
This is where the measurement earns its keep. Shorts have so little leg below the crotch that an inseam becomes a poor guide, and two shorts with the same 5 inch inseam can sit at very different points on the thigh depending on the rise.
The Oversized Shorts in heavyweight cotton run 45 cm at S, 46.5 cm at M and 48 cm at L. Those are outside lengths, and they tell you the hem lands near the knee.
When a shorts listing quotes a bare length in inches, assume it means the outseam.
Converting an outseam to an inseam
Subtract the rise. Since most listings do not publish the rise, the table below assumes a typical shorts rise of 28 cm to 30 cm, or roughly 11 to 12 inches.
| Outseam | Approximate inseam | Where the hem sits |
|---|---|---|
| 15 in / 38 cm | 3 to 4 in / 8 to 10 cm | Upper thigh |
| 16 in / 41 cm | 4 to 5 in / 10 to 13 cm | Mid thigh |
| 17 in / 43 cm | 5 to 6 in / 13 to 15 cm | Above the knee |
| 18 in / 46 cm | 6 to 7 in / 15 to 18 cm | Just above the knee |
| 19 in / 48 cm | 7 to 8 in / 18 to 20 cm | At the knee |
Treat it as an estimate, not a conversion. A dropped or high rise moves every row. If the exact figure matters, measure the inseam directly on a pair you own.
On full-length trousers, subtract 25 cm to 32 cm instead, taking the higher end for a high-waisted cut.
What the outseam will not tell you
It is a single vertical line, so it says nothing about width.
Two pairs with an identical outseam can have a 44 cm leg opening or a 52 cm one, and they will look nothing alike. The wide-leg cuts make that obvious: a wider hem drapes lower over the shoe, so the trouser reads longer than the tape says.
It also says nothing about the rise, which is the measurement that actually decides how a pair feels when you sit down.
Checking it yourself
Lay the trousers flat, square the legs up, and run a tape from the top edge of the waistband straight down the outer edge to the hem. Keep it flat and do not follow the flare.
Allow 2 cm to 3 cm either way. Hand measurement varies, and two sizes sitting within 3 cm of each other are inside the margin of error. Our how we measure page sets out what each column on a chart describes and how far to trust it.
Where to go next
The full procedure is in how to measure the outseam on pants. For the other side of the leg, see where the inseam is on pants, and for size labels, length versus inseam. Shop the range in pants and shorts.