How do I measure crotch depth?

Sit on a hard flat chair. Measure from the waist (where you want the trouser waistband) straight down the side to the chair seat. This is your body crotch depth. Add ease for comfort.

How much ease should I add to crotch depth?

Add 1.5-2.5cm ease for fitted trousers. Add 3-5cm for comfortable/relaxed fit. More ease gives a lower crotch point. Jeans typically have 2.5cm ease; palazzo trousers may have 5cm or more.

What is the difference between crotch depth and rise?

They refer to the same measurement: the distance from the waist to the crotch seam. Front rise is measured along the centre front; back rise along the centre back. Back rise is typically 3-5cm longer than front rise.

How do I adjust crotch depth on a pattern?

To lengthen: cut the pattern horizontally between waist and crotch curve, spread by the needed amount. To shorten: overlap the same amount. This adjusts rise without changing the leg length.

SewCalcs

Crotch Depth Calculator — Trouser Rise

Calculate crotch depth adjustments for trousers.

Waist to Floor

Side, waist to floor

Inside Leg

Crotch to floor

Ease

1.5-2.5cm fitted, 3-5cm relaxed

How We Calculate This

Crotch depth is calculated by subtracting the inside leg measurement from the waist-to-floor measurement. Ease is added for comfort.

The formula

Crotch depth = Waist to floor - Inside leg

With ease = Crotch depth + Ease

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.