Adjust a block
A block drafted from a table is a starting point, not a finished pattern. Sewing it up in cheap fabric first shows you what the numbers could not — and the changes you make there are what turn it into your block.
Sew a toile first
Use muslin, calico, or an old sheet — something that behaves roughly like the fabric you plan to use. Sew it with wide seam allowances so you have room to let out, mark the balance lines, and skip every finish that will not change the fit.
What to look for
Tightness, excess fabric, wrinkles, and pulling. Drag lines point towards the place that needs more room; folds point away from the place that has too much.Fitting checklist
- Cut muslin: Use inexpensive fabric that behaves similarly to your final fabric.
- Wider seams: Use 2.5 cm seam allowances so you can let seams out.
- Test movement: Sit, bend, reach, and walk in the garment.
- Mark issues: Use pins, chalk, or tape to mark problem areas.
- Photograph it: Front, back, and both sides — problems are easier to see in a photo.
- Document changes: Note what you adjusted and why.
Common fit adjustments
Change one thing at a time. Most adjustments move a line that another adjustment depends on, so a stack of simultaneous changes is hard to unpick when the next toile fits worse.
| Issue | Cause | Solution | Pattern change |
|---|---|---|---|
| Tight across bust | Insufficient ease or wrong cup size | Add width to front pattern | Slash and spread at bust line |
| Gap at back neck | Shoulder slope or neckline too wide | Adjust shoulder line | Lower back neckline |
| Sleeve too tight | Insufficient sleeve cap ease | Add width to sleeve | Increase sleeve width and cap |
| Pulling at waist | Waist too small or wrong placement | Adjust waist measurement | Add width or move waistline |
Transfer the changes back
Unpick the toile, or measure the pinned-out amounts, and move the same distances on the paper or digital pattern. Keep seam lines meeting: if you take 1 cm out of a side seam on the front, the back has to lose the same amount, and any notch has to move with it.
Then sew another toile. Two or three rounds is normal for a first block, and once it is right you have a shape that every future garment can start from.
Write down what you changed
The same adjustments usually come back on the next block. A short note — what you altered, by how much, and why — saves repeating the whole fitting from scratch.