Multi-size patterns are super helpful when you want to customize garments to your own measurements. Everyone’s shape is different, and adding sizes to a pattern lets you extend its range so it fits you (or someone else) better. This technique gives you more freedom, not just to adjust up or down, but also to experiment with different styles and fits. It’s a tool every sewist should have in their toolbox.
What You’ll Need
- Ruler
- Pencil
- Scissors
- Tracing paper or see-through paper (silk paper works well)
- OPTIONAL: tracing wheel and tracing paper
Step 1: Understand the Grading
Look at the pattern’s sizing guide. Measure the difference between adjacent sizes (e.g. between the largest and next-largest, or smallest and next-smallest). This tells you the grading increment. Often bust, waist, and hip increments are the same, but always double-check, because sometimes they differ.
In our guide, for example, the difference between sizes is 4 cm (1 1/2″).
Compare the pattern measurements to your body measurements. For example: if your bust is 115 cm, and the pattern’s XL bust is 109 cm, subtract (115 − 109 = 6), then divide by the grading increment (4 cm in this example): 6 ÷ 4 = 1.5. This tells you how many size increments you need to add.
Usually you’ll round to whole numbers (e.g. “2 sizes up”) unless the grading increment is large (≥ ~6 cm). For very precise fit in critical areas, you could use half-increments, but whole numbers are much easier.
You’ll want to repeat this comparison for all the relevant measurements: bust, waist, hips (or whichever points are important for the garment). If you’re mostly concerned with the bust, you may focus there; but if the fit around waist/hips also matters, measure those too.
Step 2: Prepare the Pattern
Print the pattern, following the designer’s printing/assembly instructions. You’ll find ours here. If the PDF has layers (i.e. separate size lines visible), hide all sizes except the two you’ll be grading between (e.g. the two largest sizes if grading up, or two smallest if grading down). This reduces clutter and helps you see clearly.
Step 3: Apply the Grading Rules
Choose a point on the pattern (corner, notch, inseam, etc.) and draw a line between the two size outlines. This line shows the direction in which the pattern will be graded.
Measure the distance between those two size outlines at that point.
Multiply that distance by the number of size increments you need (from Step 1). That gives you how far outside (to increase) or inside (to decrease) you need to move that point. Mark it.
Repeat this for all relevant points: corners, notches, seam starts, ends, etc. Work one pattern piece at a time to avoid errors. Trace the new points.
Once all points are marked, connect them carefully, maintaining the original curve of the design. Curves (like armholes, sleeves, crotch curves) are especially important: if you don’t match the curve shape, the fit will feel off.
You can also use this technique to grade only one area of a pattern. For instance, if your hip measurement doesn’t fit into the sizing range, or if your measurements correspond to different sizes (e.g. your waist is M and your hips are S).
Step 4: Trace or Transfer the New Pattern
If pattern pieces overlap or are hard to cut directly, place see-through paper over the pattern and trace the new outlines. Otherwise, use a tracing wheel with tracing paper: set regular paper underneath, the tracing paper between layers, and “trace” along the new outline. The pressure will transfer markings to the bottom layer. Protect your work surface (cut mat, cork, etc.).
Alternatively, if you’re confident, you can cut directly on the pattern following your new outlines.
Make a note somewhere on the pattern of how many sizes you added (or subtracted). It helps if you come back to it later.
Tips & Cautions
- If you are grading 4-5 sizes or more, it’s strongly recommended to make a toile (a test garment) first. Big size changes can introduce fit issues you won’t see until trying it on.
- Be sure every important marking (notches, grain lines, darts, etc.) is carried over or re-marked, so construction instructions still make sense.
- Ensure that internal angles and curves are preserved, don’t distort them.