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Button Spacing Calculator: Positions and Layout
Mark button positions before sewing. Enter the placket length, end margins, and button count to get every center from both edges, a layout, and an exportable marking list. An inverse mode finds a count from your maximum spacing, and an optional anchor keeps a button at a chosen position.
The button marking desk
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Worked example
For a 50 cm placket with a 3 cm top margin, a 2 cm bottom margin, and six buttons, the first-to-last span is 45 cm. Five intervals are 9 cm each. Centers are at 3, 12, 21, 30, 39, and 48 cm from the top.
| Button | From top (cm) | From bottom (cm) | Gap from previous (cm) | Estimated buttonhole (cm) |
|---|---|---|---|---|
| 1 | 3 | 47 | Not determined | 1.5 |
| 2 | 12 | 38 | 9 | 1.5 |
| 3 | 21 | 29 | 9 | 1.5 |
| 4 | 30 | 20 | 9 | 1.5 |
| 5 | 39 | 11 | 9 | 1.5 |
| 6 | 48 | 2 | 9 | 1.5 |
How to use it
Replace the example with your values and check units. Results update as you edit. Keep a scenario to compare, then export a file; this tool’s JSON can restore your inputs.
Worked example
For a 50 cm placket with a 3 cm top margin, a 2 cm bottom margin, and six buttons, the first-to-last span is 45 cm. Five intervals are 9 cm each. Centers are at 3, 12, 21, 30, 39, and 48 cm from the top.
Method and sources
Without an anchor, spacing equals (length − top margin − bottom margin) / (count − 1). A single button is centered in the usable span. Inverse mode rounds the number of intervals up to keep spacing within your maximum. With an interior anchor, the nearest interior button is fixed at that mark; each side is distributed separately while the end margins remain unchanged. Conversions use exactly 1 inch = 2.54 cm. Diameter checks overlap. Buttonhole ease is your entered allowance.
- New Mexico State University — Machine Buttonholes Made Easy
- Rascol — placement de boutons
- Sussex Seamstress — mesure entre centres
Sources checked November 1, 2026.
Starting values are a fictional example. The method and limits below describe what is actually calculated.
Who it is for, and limits
The diagram is a visualization, not a full-size pattern. An anchored button can create two different spacings; both are shown. Buttonhole length also depends on thickness and fabric, so test on a scrap. This calculation does not correct an undersized garment or infer body size.
Common questions
What distance goes between buttons?
The calculation gives center spacing from your margins; it does not recommend a universal distance.
Can I anchor one button?
Yes, with at least three buttons and an interior mark. The two spans are distributed separately.
How many buttons keep a maximum gap?
Inverse mode rounds the interval count up, then adds one button.
How long should the buttonhole be?
The result adds your entered ease to the diameter. Test with the actual button and a fabric scrap.
Is the drawing a full-size pattern?
No. Use the table measurements for marking; the SVG is a reference diagram.