Pattern drafting
Pattern ease calculator
Turns a body measurement into a garment measurement and then a per-piece drafting figure, keeping wearing ease and design ease apart.
The question this answers: “What measurement should the pattern piece actually be?”
Result
- Finished garment measurement
- 105 cm
- 96 body + 9 ease.
- Per pattern piece
- 26.3 cm
- Divided across 4.
- Per piece, with seam allowance
- 28.3 cm
- Adds 1cm at each of two edges.
- Ease breakdown
- 5 + 4 cm
- Wearing, then design. Kept apart deliberately.
Worth knowing about this answer
- Wearing ease and design ease are different quantities and this keeps them apart on purpose. Merging them is the commonest conceptual error in drafting.
- Whether your blocks already include seam allowance is a decision to make once and write on the pattern. Adding it twice, or not at all, accounts for a great many garments that come out the wrong size.
- These figures are geometry, not fit. Only a toile tells you whether the ease is in the right places.
Show the working
- Total ease
5 + 49 cm - Garment measurement
96 + 9105 cm - Per piece
105 ÷ 426.3 cm - With allowance
26.3 + (1 × 2)28.3 cm
Finished garment measurement: 105 cm. Per pattern piece: 26.3 cm. Per piece, with seam allowance: 28.3 cm. Ease breakdown: 5 + 4 cm
Body measurement plus wearing ease plus design ease gives the finished garment measurement. That divided by the number of pieces gives the per-piece figure, and two seam allowances are added for the two cut edges.
- The measurement divides evenly across the pieces, which is true for a simple bodice or trouser block and not for asymmetric designs.
- Two cut edges per piece on the measured line.
- Geometry, not fit. Only a toile tells you whether the ease is in the right places, and ease distributed wrongly fits worse than too little ease distributed well.
- It cannot know whether your blocks already carry seam allowance. That is a decision to make once and write on the pattern.
- Stretch fabrics work on negative ease and different rules; this is drafted for wovens.
Runs entirely in your browser — nothing you type is sent anywhere. Last reviewed 2026-08-15. More on Pattern drafting.