How to Grade a Sewing Pattern in Adobe Illustrator (Step by Step)

Have you ever wondered how to grade a sewing pattern in Adobe Illustrator?

You don’t need expensive grading software like Gerber or StyleCAD to do it. I’m going to show you the exact way I graded one of my own patterns, a zipper shirt I drafted for myself, into three more sizes. It’s a lot faster than you might think!

The short version

→ Put each size on its own layer, so you can lock, hide, and check each one.
→ Copy your pattern and Paste in Front (Ctrl/Cmd + F) onto every size layer.
→ Work out your grade amounts first. That’s how much each point moves for each size.
→ Select the anchor points with the Direct Selection tool and use Object > Transform > Move to move them by your grade amount.
→ Lock the size you just finished, then use Transform Again (Ctrl/Cmd + D). The bigger sizes keep moving, one step at a time.
→ Grade on the stitch line, and add seam allowance last.

What pattern grading is

Grading is taking one pattern and making it bigger or smaller to create a full size range. Each point on the pattern moves a set amount for each size. Those amounts are called grade rules.

The math behind your grade amounts is its own topic. I break it down in my video Garment Grading Math That Actually Makes Sense. This post is all about the Illustrator part: how to actually move the points once you know your numbers.

How to grade a pattern in Illustrator, step by step

Step 1: Make a layer for each size

Open your pattern and add a layer for every new size. I added three and named them Up 1, Up 2, and Up 3. You can name them Small, Medium, Large, or whatever makes sense for your size chart.

I keep all my pattern information (labels, grainlines, notes) on the bottom layer. That way, if I hide every other layer, I can still see which piece is which.

Keep your Layers panel open the whole time. You’ll be locking and unlocking layers a lot, and it helps to see them all at once.

Step 2: Copy your pattern onto every layer

Lock your information layer so you only copy the pattern lines, not the words.

Select the pattern, copy it (Ctrl/Cmd + C), click on the next layer, and Paste in Front (Ctrl/Cmd + F). Paste in Front drops the copy in the exact same spot as the original. Do this for each size layer.

To double check, turn the layers on and off one at a time and make sure each one has a full copy of the pattern.

Step 3: Work out your grade amounts

Before you move anything, decide how much each size grows.

For this shirt, I added 5/8″ to each side of the front and back pattern pieces, and made each size 1/4″ longer. This shirt only grades out and down. I kept the neckline the same on purpose because of the design. On most patterns, like a basic bodice block, you’d also grade the neckline and the armhole.

Step 4: Lock the original and move the first set of points

Lock your original size layer. It stays exactly where it is.

With the Direct Selection tool, select just the anchor points on one side of the pattern. Then go to Object > Transform > Move. For this shirt, I moved them 0.625″ horizontally and 0.25″ vertically.

Turn on the Preview checkbox. You’ll see where the points are going before you click OK, so you know you’re moving them in the right direction.

A viewer shared a great shortcut for this: Shift + Ctrl/Cmd + M opens the Move window, so you don’t have to dig through the menu.

Step 5: Lock and Transform Again for each bigger size

This is my favorite part.

After that first move, all of your size layers moved one step. Now lock the Up 1 layer and use Transform Again (Ctrl/Cmd + D). Only the unlocked layers move, so Up 2 and Up 3 move one more step. Lock Up 2 and Transform Again, and Up 3 moves one more time.

That’s one side of the pattern graded through every size.

Step 6: Grade the other side

Unlock all your size layers (keep the original locked), select the anchor points on the other side, and move them the opposite way horizontally. I used -0.625″ horizontally and 0.25″ vertically, so the points go out and down. Then lock and Transform Again, the same as before.

If you deselect by accident, just reselect your points and keep going.

Step 7: Don’t forget the center points

The points along the center of the pattern don’t move out, only down. For those, I moved 0″ horizontally and 0.25″ vertically, then locked and repeated through each size.

It’s easy to miss these, so zoom in and check. If you’re moving fast, some points might not move with the rest.

Step 8: Double check your sizes

Measure a few lengths on each size to make sure your math worked out and every size is what you wanted. I always double check. It’s so much easier to fix now than after someone sews it.

Tips for cleaner grading

→ Grade on the stitch line, not the cut line. I draft and finalize my patterns on the stitch line, and adding seam allowance is the last thing I do.
→ Make each size easy to spot. I like to keep all the lines black and give each size a different dashed line style, like dots, dashes, or a mix. Then add a chart that shows which line goes with which size.
→ Grading well comes down to details. Whether you grade by hand, in Illustrator, or in pattern software, it’s the attention you give each step that makes the difference.

Quick answers to common questions

Want to learn grading the whole way through?

This video is a quick look at my process. If you want the full picture, my Pattern Grading Pro course walks you through it step by step: the grading math, building grade rules, the grid and anchor-point methods, and checking and exporting every size in Illustrator and CLO3D.

Happy patterning,
Christina