Start with measurements and a basic block
Making a shorts pattern begins with measuring the person who will wear them, then drafting a straightforward rectangular block on paper. You do not need to buy a commercial pattern — a basic block takes about 30 minutes to draft and becomes the foundation for any shorts style you want to sew.
Measure waist, hip, inseam (inside leg from crotch to ankle), and outseam (outside leg from waist to ankle). Write these down. You will also need the distance from waist to hip (usually 7 to 9 inches) and the width across the back at hip level. If you are drafting for yourself, stand in front of a mirror with a measuring tape held level at your hips — that hip measurement is what matters, not what your jeans say.
Use a large sheet of paper (pattern paper or kraft paper works), a ruler, and a pencil. Draw a rectangle with the width equal to one-quarter of your hip measurement plus 1 inch for seam allowance. The height is your inseam measurement. This rectangle is your basic leg block. You will add the waistband and shape the crotch curve from here.
Key Takeaways
- A basic shorts block is a rectangle based on one-quarter of hip measurement and inseam length, which takes 30 minutes to draft on paper.
- You need five measurements: waist, hip, inseam, outseam, and waist-to-hip distance, all taken while standing straight in front of a mirror.
- The crotch curve is the most important shaping — it prevents the shorts from pulling or sagging and is drawn freehand or traced from an existing pair.
- Seam allowances (usually 5/8 inch) must be added to all edges before you cut fabric, or marked clearly on the pattern so you add them while cutting.
- Test your pattern by sewing a muslin sample first, which shows you where the fit needs adjustment before you cut expensive fabric.
Draw the crotch curve and leg shaping
The crotch curve is what separates a flat pattern from shorts that actually fit. On your basic rectangle, mark a point about 1 inch down from the top on the inside leg line (the center front). From that point, draw a gentle curve that dips down about 2 to 3 inches at the deepest point (roughly one-third of the way across the leg width), then curves back up to meet the side seam at hip level.
This curve should be smooth, not sharp — use a flexible ruler or trace along the curve of an existing pair of shorts you own that fits well. The back crotch curve is similar but slightly deeper, dipping about 3 to 4 inches. If you are new to pattern drafting, tracing an existing pair is faster and more reliable than calculating the curve mathematically.
Once the crotch is shaped, add the inseam by drawing a line from the bottom of the crotch curve straight down to the ankle. The outseam (outside leg) should angle slightly inward from hip to ankle — about 1/2 inch narrower at the ankle than at the hip. This taper prevents the shorts from looking baggy at the leg opening.
Add waistband allowance and seam margins
At the top of your pattern, extend the paper 1.5 inches above the waist line. This extra space is where the waistband will attach. Mark a line 1.5 inches above the original waist line — this becomes your cutting line for the shorts body.
Now add seam allowances to every edge: 5/8 inch is standard for home sewing. You can either draw a second line 5/8 inch outside your pattern outline (the cutting line), or write "add 5/8 inch seam allowance" clearly on the pattern and add it while cutting fabric. Many sewers prefer to mark the seam allowance line on the pattern itself so there is no confusion at the cutting table.
Mark grain line arrows on your pattern — these should run parallel to the inseam, pointing toward the ankle. Grain line matters because fabric stretches differently in different directions, and shorts cut off-grain will twist and pull when you wear them.
Create front and back pattern pieces separately
Your basic block is symmetrical, but shorts front and back are not. The back is wider at the hip and has a deeper crotch curve. Trace your basic block twice on fresh paper. On one copy, label it "Front" and keep the crotch curve as you drew it. On the second copy, label it "Back" and redraw the crotch curve 1/2 to 1 inch deeper.
The back hip width should be about 1/2 inch wider than the front on each side seam. Adjust the side seam line outward slightly on the back piece. The back waist can also be 1/2 inch wider than the front waist to account for the seat — this prevents the waistband from pulling or twisting.
Mark both pieces clearly with grain line, seam allowance lines, and notches at the side seams and inseams so you can match them correctly when sewing. Notches are small cuts or marks that help you line up pieces accurately.
Test the pattern with a muslin sample
Before cutting your fashion fabric, cut a test pair from muslin or an old cotton sheet. Muslin is inexpensive and shows fit problems clearly. Sew the muslin shorts together using the same seam allowances as your pattern, then try them on.
Look for pulling across the hip, sagging at the crotch, or twisting at the side seams. If the crotch pulls, the curve is too shallow — redraw it deeper. If there is excess fabric at the crotch, the curve is too deep. If the waist gaps or pulls, adjust the waist measurement on your pattern. Mark all changes directly on the muslin with a pen, then transfer those changes back to your paper pattern.
This test step saves time and fabric. A muslin sample costs a few dollars and prevents cutting an expensive piece of linen or cotton the wrong way.
Adjust for different shorts styles
Once your basic block fits, you can modify it for different styles. For longer shorts (bermudas or walking shorts), extend the inseam line down to knee length or below. For shorter shorts, shorten the inseam but keep the same hip and waist measurements — the fit at the top is what matters.
For wider leg shorts, increase the width at the ankle instead of tapering inward. For fitted shorts, taper more aggressively — 1 to 1.5 inches narrower at the ankle. For shorts with a drawstring waist, you can reduce the waist measurement by 2 to 3 inches because the drawstring will cinch it.
Keep your original basic block pattern in a safe place. Each time you modify it for a new style, trace it onto fresh paper and make the changes on the copy. This way you always have the original to return to if an experiment does not work.
Document your pattern for future use
Write the following information directly on your pattern pieces: your name, the date, the measurements used (waist, hip, inseam), and any notes about fit or style. Include the seam allowance amount and the grain line direction. If you made changes during the muslin test, write those down too — "deepened crotch curve 1/2 inch" or "added 1 inch to waist".
Store your pattern flat in a folder or envelope. Patterns fold and crease, but they last for years if kept dry and away from direct sunlight. If you sew the same shorts style multiple times, you will refer back to these notes and know exactly what worked.
Frequently Asked Questions
Do I need special pattern paper to draft shorts?
No. Kraft paper, newsprint, or even the back of old wrapping paper works fine for drafting. Pattern paper (the kind with a grid) makes measuring easier, but it is not required. What matters is that the paper is large enough and that you can write on it clearly with a pencil.
What if my measurements are between sizes?
Draft for the larger measurement. Shorts that are slightly loose fit better than shorts that are tight. You can always take in a seam later if needed, but you cannot add fabric back. If your waist is 28 inches and your hip is 36 inches, draft using those exact numbers rather than rounding to a standard size.
Can I use a commercial pattern as my starting point?
Yes. Trace a commercial shorts pattern that fits you well, then modify it by adding or removing width at the seams. This is faster than drafting from scratch and gives you a proven fit to build from. Mark your changes on the traced copy so you remember what you adjusted.
How do I know if my crotch curve is the right depth?
The muslin test is the only reliable way. If the shorts pull at the crotch when you sit or bend, the curve is too shallow. If there is wrinkles or excess fabric bunching at the crotch, the curve is too deep. Adjust in small increments — 1/4 inch at a time — and test again.
Should I add extra length for hemming?
Yes. Add 1 to 1.5 inches to the inseam length on your pattern so you have fabric to fold up and stitch a hem. This also gives you room to adjust the length if the shorts are slightly longer or shorter than expected after sewing.