How to make a toile (muslin) to test the fit

A toile, called a muslin in the US, is a quick test version of a garment sewn in inexpensive fabric that behaves like your final fabric. You cut it from the pattern with the seam lines marked, sew it with long stitches, try it on, pin out or open up anything that does not fit, then copy those changes to the pattern before you cut into the fabric you care about. A bodice toile takes an evening; it can save a whole garment.

When do you need a toile?

Make one when the fit is close to the body or the fabric is precious:

• fitted bodices, fit-and-flare dresses and anything with darts and a zip;
• pencil skirts, trousers and other close-fitting bottoms;
• set-in sleeves in a fitted armhole;
• expensive, scarce or hard-to-unpick fabric such as silk, wool or a print you love;
• the first time you use a new pattern or new measurements.

You can usually skip it for loose shapes where a centimeter or two does not matter: gathered and elastic-waist skirts, kimono jackets, relaxed tees in a forgiving knit, tote bags, aprons and cushion covers. In between, sew a wearable toile: the real pattern in a cheap fabric you would still wear if it works.

Which fabric should you use for a toile?

The toile has to behave like the final fabric, or it tells you about the wrong garment.

The cheap cotton itself is called muslin in the US and calico in the UK, where muslin means a fine open weave. Secondhand bedsheets are an excellent source of toile fabric. For knits, check the stretch percentage of both fabrics with the same test before you cut.

What to include, and what to leave out

Sew only what affects fit. Include the main body pieces, the darts, one sleeve (most bodies are symmetrical enough to fit one) and, on skirts and trousers, the waistband, because it decides where the garment sits. Leave out facings, linings, pockets and trims. Press up the hem allowance instead of hemming, so you can judge the length. For the opening, baste it closed on the seam line and pin yourself in, or put in a cheap regular zip on very fitted garments.

How to make a toile, step by step

1. Prepare the pattern. Print it at true scale and check the 5 cm (2 in) test square before assembling the pages.
2. Cut with generous allowances. Keep the pattern's seam allowances, and cut 2.5 cm (1 in) on the side seams so there is room to let the toile out.
3. Mark everything. With a felt-tip pen, draw on the right side the stitching lines, center front and center back, the bust point, the waist and hip lines and the grainlines. When you wear the toile, the horizontal lines should be level and the vertical ones plumb.
4. Staystitch the curves. Sew around the neckline and armholes 3 mm (1/8 in) inside the seam line so they do not stretch as you try the toile on and off.
5. Baste it together. Sew the darts first, then the shoulders, side seams and the sleeve, with a long stitch of 4 to 5 mm in a contrasting thread. Basting stitches unpick in seconds when you need to adjust.
6. Press every seam open. Clip the neckline and armhole allowances so the curves lie flat; an unpressed toile always looks worse than it fits.
7. Try it on right side out, wearing the underwear and shoes you will wear with the garment, and pin the opening closed exactly on the seam line.

How to fit a toile

Stand naturally in front of a mirror, then take photos from the front, side and back: wrinkles are easier to read in a photo. Check, from the top down, that:

• the shoulder seams sit on top of the shoulders and end at the shoulder bone;
• the side seams hang straight down and the center lines stay centered;
• the bust, waist and hip lines are level all round;
• the bust darts end 2 to 2.5 cm (3/4 to 1 in) from the bust point;
• the armholes neither cut in under the arm nor gape;
• the neckline lies flat without gaping or pulling;
• the hem and sleeves are the length you want.

Then move: lift your arms, reach forward, sit down, walk and bend. A woven garment that only fits while you stand still needs more ease. To read specific wrinkles and fix them, see fixing common fit issues.

Marking changes and transferring them to the pattern

1. Where the toile is loose, pin out the excess in a fold or along a seam, and draw a line on both sides of the pinned fold before you unpin it.
2. Where it pulls, unpick the seam or cut into the toile until it lies smooth, measure the gap and fill it with a strip of fabric or paper tape.
3. Write each amount and its direction on the toile itself: "+1.5 cm at bust", "-1 cm shoulder".
4. Take the toile off, lay it flat, and copy the new lines onto the pattern.
5. True the seams: pieces that are sewn together must still be the same length, curves must flow smoothly across seams, and notches must line up.
6. Carry each change to the pieces that depend on it: a lowered neckline changes the facing, a deeper armhole changes the sleeve.
7. If you changed anything by more than about 2 cm (3/4 in), sew a second toile. Changes interact, and a second test is quick once the first is done.

A toile with a made-to-measure pattern

When a pattern is drafted from your own measurements, the toile is less about size and more about ease, style and catching a wrong measurement. If the toile shows that a number was off, such as a waist measured too tight or a back waist length too short, correct it in Sewly and the pattern redraws instantly; then print the corrected pieces, which needs a paid plan. The 3D preview helps you judge proportions and length before you cut, but it shows the silhouette, not how a particular fabric drapes, so the toile remains the test of real fabric on a real body. Measuring carefully in the first place saves the most time: see how to take your body measurements.

Common toile mistakes

• A toile fabric too different from the real one. Stiff calico for a viscose dress makes it look tight and boxy; match the weight and drape.
• No seam lines marked. Without them you cannot tell how much you pinned out.
• Fitting it inside out. Your left and right are swapped, and any asymmetry ends up on the wrong side.
• Over-fitting. Pinning out every bit of ease while standing still gives a garment you cannot sit down in.
• Fitting on a dress form only. A form does not have your posture; use it for a first look, then try the toile on yourself.