Button Spacing Calculator — Even Placement

Subtract the top and bottom offsets from the placket length, then divide by the number of gaps (buttons minus 1). This gives the distance between each button centre.

Buttonhole length equals the button diameter plus 3mm. For thick or domed buttons, add the button thickness as well. Always test on a scrap of fabric first.

The top button is usually 1.5-2.5cm from the neckline edge. The bottom button is 2-3cm from the hem. For women’s shirts, place a button at bust level to prevent gaping, then space the rest evenly.

Mark buttonhole positions on the overlap side first. Sew the buttonholes, then lap the garment closed and mark button positions through the buttonholes to ensure perfect alignment.