Ease Calculator
Ease is the difference between your body and the pattern. Too little and it pulls; too much and it bags. Measure your pattern piece, enter your body measurement, and we'll tell you if the ease is right for the fit style you want.
What is ease?
Ease is the difference between your body measurement and the finished garment measurement. A body measurement of 40" at the bust and a finished bust of 43" means 3" of ease. Without ease, a garment couldn't be put on — or moved in.
There are two types. Wearing ease is the minimum needed for comfort and movement — the amount that lets you breathe, sit, and raise your arms. Design ease is additional ease added deliberately by the designer for a specific silhouette — a boxy top has more design ease than a fitted one.
Pattern companies include ease in their patterns, but they don't always tell you how much. Measuring the pattern and checking against your body is the only way to know for certain.
How to measure the pattern
Always measure the seamline, not the cutting line. The seamline is 5/8" (or 1.5 cm) inside the cutting line on most patterns — seam allowances are not part of the finished garment and should not be included in ease calculations.
For circumference measurements (bust, waist, hip), add up all the relevant pattern pieces. A typical bodice bust measurement = front bodice seamline + back bodice seamline, measured horizontally at the bust level, then multiplied by 2 if you only have one front and one back piece (they get cut twice on the fold or as mirror pairs).
Use a flexible tape measure held on its edge to follow curved seamlines accurately. For straight seams, a rigid ruler is fine.
When ease ranges don't apply
Stretch fabrics(knits, jersey, lycra blends) often use negative ease — the garment is smaller than the body and stretches to fit. A fitted knit top might have −1 to −2" of ease at the bust. The ranges in this tool assume woven fabric; for knits, a negative result is expected and correct.
Structured garments like tailored jackets and coats are shaped by interfacing (also called interlining or Vilene), padding, and construction — they may need more ease than the ranges suggest, especially through the chest and upper back, to accommodate the structure.
When in doubt: sew a muslin (toile) and check fit on the body. No calculator replaces wearing the garment.