How to draft a basic pants pattern

What you will learn

Learn the measurements and the pieces that make up the base pants pattern, understand what the hip line and the rise line are for, and know what to correct before grading the pattern to the whole size range.

Before you start

You need the measurement chart for the base size you are going to draft: your target customer's, or an industry reference chart. No chart is a fixed standard, so you will confirm it afterwards with a sewn sample.

Concept

The base pants pattern is built from two flat pieces, front and back, drafted from six measurements: waist circumference, hip circumference, rise, total length, knee circumference and hem circumference. Two horizontal lines organize that drafting across the pieces: the hip line and the rise line. The waist almost always measures less than the hip, so the pattern has to absorb that difference without leaving a loose pocket of fabric: with darts in dress pants or with an elasticated waist in joggers. And before grading that pattern to the whole size range, it has to be tried in fabric and corrected, so you don't repeat a fit error in every size of the production run.

Lesson content

The 6 measurements of the base pattern

The measurements you need are of two types: circumferences, which are taken by wrapping the tape measure around the body, and lengths, from one point to another. The one that is hardest to understand at first is the rise: it is the one that determines whether the pants fit properly or end up out of place.

Waist circumference: where the waistband sits.
Hip circumference: at the widest point, between 18 and 22 cm below the waist depending on the body (approximate).
Rise (crotch depth): from the waist to the crotch, measured underneath, taken with the person seated on a hard surface.
Total length: from the waist to the floor, or to the hem you want to give it.
Knee circumference: determines whether the pants end up straight, skinny or wide in that area.
Hem circumference: the final width of the leg at the bottom.

The pieces: front, back, waistband and pockets

The front and the back are each cut in duplicate, one for each side of the body. The front has less rise and less dart because the body is flatter at the front; the back has more rise and a more pronounced curve because it covers the seat without fitting too tightly.

To those two pieces you add the waistband (or an elasticated waist that replaces it) and the pockets, which change in shape and position depending on the style.

Front (cut x2).
Back (cut x2).
Waistband, built or replaced by an elasticated waist.
Front and/or back pockets.
Belt loops, common in dress pants.

Dress pants or joggers, women's or men's: what changes in the draft

Dress pants are cut from woven fabric (gabardine, twill, denim), have darts at the waist, a waistband built with interfacing and a zip fly: they demand precision because in a fabric that doesn't give, any badly distributed excess shows. Joggers are cut from knit fabric and resolve the waist-to-hip difference with an elasticated waist (elastic plus drawstring) and no darts, because the fabric stretches; the rise, the knee and the hem are defined the same way as in dress pants.

The women's and the men's body also distribute that difference differently: in women's the hip is usually proportionally larger, so the pattern carries more dart or pleat, and the rise is usually shorter than in men's for a similar hip. The fly also changes: centered in men's, centered or shifted to the side in women's. It is not the same base with the waist moved: they are two different developments.

Why test the pattern before grading it

Once the base size is drafted, cut it in a fabric similar to the final one and sew a sample. That is where what the paper doesn't show appears: whether the rise curve pulls tight or hangs loose, whether the waist is loose and whether the real length matches the intended one.

With the sample on, you correct the pattern on paper or in the digital file, and only then does it make sense to grade it: waist, hip, rise, length, knee and hem don't all grow by the same amount from one size to the next, and grading without testing multiplies any fit error in every size of the production run.

Step by step

Confirm the measurement chart for the base size: waist circumference, hip circumference, rise, total length, knee circumference and hem circumference, from your target customer or from a reference chart.
Draw the base rectangle with the total length and half the hip circumference plus ease.
Draw the hip line, measuring down from the waist the hip height you took.
Draw the rise line, which marks the depth of the crotch.
Develop the front with less rise and less dart, and the back with more rise and a more pronounced curve; each one is cut x2.
Resolve the difference between waist and hip with sewn and pressed darts (dress pants) or with pleats and an elasticated waist (joggers).
Define the knee circumference (straight, skinny or wide) and the hem circumference according to the style.
Add the waistband (or the elasticated waist) and the pockets according to the style you are developing.
Cut the base-size pattern in a fabric similar to the final one and sew the sample.
Try on the sample: check whether the rise curve pulls tight or hangs loose, whether the waist is loose and whether the length matches what you intended.
Correct the pattern on paper or in the digital file with what the fitting showed.
Only once the pattern is corrected, grade it to the whole size range.

Practical example

A basic dress pants pattern is built, at a minimum, from a front and a back (each one cut x2), plus a waistband and side or welt pockets; joggers swap that built waistband for an elasticated waist and have no darts.

Common mistakes

Grading the pattern to the whole size range without having tested it in fabric first.: Cut and sew the base-size sample first: that is where the rise curve, the waist-to-hip fit and the length get corrected. Grading a pattern without testing it multiplies any fit error in every size.

Thinking that the women's pattern is the same as the men's, just with the waist moved.: They are two different developments: they change how the dart is distributed between waist and hip, the length of the rise and the position of the fly, even though they share the logic of the hip line and the rise line.

Modeltex tip

If you need to produce pants to sell without spending weeks on development, the Modeltex catalog includes dress pants, joggers, cargo pants, chinos and uniform pants patterns, for women, men and kids, with the full size range already graded and approved with a sewn sample, in PDF A4, PDF plotter or the CAD formats your workshop uses.

Exercise

Take the 6 measurements — waist, hip, rise, total length, knee and hem — of a real person or of yourself, and write them down on a sheet. Then find a pair of pants you already own: identify the front, the back, the waistband and the pockets, and see whether it resolves the difference between waist and hip with darts or with an elasticated waist.

Frequently asked questions

How do you make a pants pattern?

It is drafted with six measurements — waist circumference, hip circumference, rise, total length, knee circumference and hem circumference — on two pieces, front and back, using the hip line and the rise line as references. The difference between waist and hip is resolved with darts in dress pants or with an elasticated waist in joggers, and before grading it, it has to be tested in fabric and corrected.

What measurements do you need for a pants pattern?

At a minimum, the waist circumference, hip circumference, rise, total length, knee circumference and hem circumference. They are starting measurements: it is best to take them from your target customer or from a reference chart and adjust them with a fabric test, because they vary with the body.

How many pieces does a pair of pants have?

In its simplest version, two: front and back, each one cut in duplicate. To that you add the waistband, when the style has one built, and the pockets, which change depending on whether it is dress pants, joggers or cargo pants.

What is the difference between a dress pants pattern and a jogger pattern?

Dress pants are cut from woven fabric, with darts at the waist to absorb the difference with the hip, a built waistband and a zip fly. Joggers are cut from knit fabric and resolve that difference with an elasticated waist, without darts, although the rise and the other measurements are defined the same way.

How is a women's pants pattern different from a men's?

Mainly in the rise, which is longer in men's for a similar hip, and in how the difference between waist and hip is distributed, which is greater in women's and calls for more dart or pleat. The fly also changes: centered in men's, centered or shifted to the side in women's.

Do you have to test the pattern before grading it to all sizes?

Yes, always. The base size is sewn as a sample to check the rise curve, the fit at waist and hip and the real length, and only after correcting those points is it graded to the whole range. Grading without testing repeats any fit error in every size.

Summary

The base pants pattern is drafted with six measurements on a front and a back, using the hip line and the rise line as references, and resolving the difference between waist and hip with darts or with an elasticated waist depending on the style. Before it is graded to the whole size range, it is tested in fabric and corrected.

Go back to the full course or ask the Modeltex Lab AI.