Why it matters: too short a rise and the trousers cut in and pull down at the back when you sit. Too long and they sag between the legs.

• Use a hard chair (a dining chair or a stool), not a sofa. A soft seat gives a short reading.
• Sit upright, feet flat, thighs level.
• Hold a ruler upright at the side of the hip; read the tape against it from the waist marker to the chair.
• Crotch length: ask the person to hold the tape end at the front waist themselves, pass it down between the legs, and hand it to the helper behind, who brings it up to the back waist. This keeps the measurement comfortable and respectful.
• Alternative: measure the crotch seam of trousers that fit, front waist to back waist along the seam (Module 6).
• Seated wearers: the back rise needs to be longer and the front shorter for comfort in a wheelchair. Measure crotch length seated, and tell the tailor.

• Fuller seat: the back crotch length is longer; give the full crotch length and where the inside leg point was.
• Flatter seat: the back rise is shorter; trousers may sag at the back if cut to a standard block.
• Fuller tummy: the front rise is longer; give a tummy round as well as waist and hip.
• Full thighs: the thigh round may be close to the hip round. Give it; the tailor needs it to avoid pulling.
• Athletic legs: calf and thigh may need more room than the standard block gives. Give both.
• Petite and tall: outseam and inseam differ from charts. The rise also scales with height: don’t assume it.
• Pregnancy: under-bump or over-bump waist; take the waist where the band will sit (Module 6).
• Older bodies: the waist may be less defined; measure where trousers are comfortable.
• Seated and adaptive: measure outseam seated to the ankle, add for the bend of the knee, and ask for side openings or elastic if dressing is hard.

• Wear the shoes for outseam; heels change it by an inch or more.
• Decide the hem break (where the hem meets the shoe): no break, slight break, full break. Say which.
• Take both inseam and outseam if you can; they check each other.
• Use a book between the legs as a crotch guide: stand with a hardback book pressed gently up between the thighs, spine level; measure from the top of the spine to the floor for the inseam to the floor.
• Measure both thighs and give the larger.
• Write “high”, “mid” or “low” waist next to the waist number.
• Measure bent knee for fitted styles: knee round can grow by an inch when bent.
• Hip at the fullest part, which can be at the thigh on some bodies; give that as the hip.
• Pocket things? Phones in front pockets need room; say so.
• Measure trousers you love laid flat; it is the most reliable check.

The trousers pull down at the back when I sit.

1. The back rise is too short: re-measure crotch depth seated, and crotch length.
2. Ask for a contoured waistband, higher at the back.
3. Prevention: always give crotch depth taken seated on a hard chair.

There are folds under the seat.

1. The back rise is too long or the seat too full in the pattern; tell the tailor “folds under the seat”.
2. Check the hip number is not too big.
3. Prevention: send a photo of trousers that fit you well at the back, on a hanger.

The front rides up into creases (“smile lines”).

1. Thigh or hip too tight; re-measure the thigh.
2. The front rise may be short; give crotch length with the inside leg point marked.
3. Prevention: give thigh round for every fitted trouser.

The hem is too short with heels.

1. Re-measure outseam in the shoes.
2. Ask for a deep hem allowance to let down.
3. Prevention: decide on the shoes before ordering.

The waistband gapes at the back.

1. Common on curvy figures with a small waist and fuller seat. Ask for a contoured waistband or back darts.
2. Give both waist and hip clearly; the difference tells the tailor.
3. Prevention: measure the waist exactly where the band sits.

My crotch depth reading changes every time.

1. Use the same hard chair and an upright ruler.
2. Check the waist marker hasn’t moved.
3. Prevention: take it three times and use the middle reading.

The knees bag out after a day.

1. That is mostly fabric, not measurement; ask for a fabric with better recovery.
2. Check the knee round is not much bigger than you need.
3. Prevention: give the bent-knee round, so the tailor knows the real room needed.

• Measuring crotch depth standing, following the curve of the hip.
• Measuring the waist at the natural waist for mid-rise trousers.
• “Waist and hip are enough for trousers.” Without the rise, the fit is a guess.
• Measuring outseam barefoot for trousers worn with heels.

1. The seated rise: take crotch depth three times on a hard chair. Within ¼ in?
2. Inseam versus outseam: take both, and check them against trousers that fit.
3. Two waists: measure natural waist and mid-rise waist. Note the difference and the distance between them.

As a hobby: trousers are a step up from kurtas. Your crotch depth and length are the key to every pattern you’ll use.

For earning: a trouser that fits at the back brings clients back. Keep seated rise on every card.

For teaching: teach crotch length with the person holding the tape themselves; it keeps the class comfortable.

• Men: the same list, with the waist at the trouser line and a separate stomach round (Module 4, Men’s trousers and kurtas).
• Children: waist, hip, outseam and, for older children, crotch depth. Elastic waists and deep hems give growth room (Module 5).

1. How is crotch depth measured? Seated on a hard chair, from the waist marker straight down to the seat.
2. What is crotch length? Front waist, down between the legs, up to the back waist.
3. Why wear shoes for outseam? Heels and soles change the length.
4. What causes trousers to pull down at the back when seated? Usually a back rise that is too short.

In the US, “pants” means trousers; in the UK, it means underwear. In Western pattern cutting, crotch depth is often called “body rise”, and crotch length “total rise”. The measuring method is the same.

• Did you tie a waist marker where the trousers will sit?
• Did you measure crotch depth seated on a hard chair?
• Did you take outseam in the shoes you’ll wear?
• Did you give thigh round for fitted styles?

• Rise (crotch depth): from waist to seat, measured seated.
• Crotch length (total rise): from front waist, between the legs, to back waist.
• Inseam: inside leg, crotch to hem.
• Outseam: outside leg, waist to hem.
• Break: how the hem meets the shoe.

• General tailoring practice. The seated crotch depth method is widely taught in pattern cutting.
• The book-between-the-legs trick is a common home method; it is less accurate than measuring trousers that fit.
• Teacher to check: which trouser measurements the studio’s card holds.