How to use the button spacing calculator
- Enter the length of the opening along the edge where the buttons will sit.
- Choose whether you know the number of buttons or the space between them.
- Enter the distance from the top to the first button and from the bottom to the last button.
- Read the space between buttons and the position of each button center measured from the top.
Formula
room between first and last = length - top distance - bottom distance
space between buttons = room / (buttons - 1)
buttons from a space = floor(room / space) + 1, then the space is evened out
When you choose the space between buttons, the page picks the number of buttons that fits and spreads the leftover room evenly, so the final space can be slightly larger than the one you entered.
Six buttons along 24 inches
With 1 inch at the top and bottom, the room between the first and last button is 24 - 1 - 1 = 22 inches. Six buttons have 5 spaces, so each space is 22 / 5 = 4.4 inches. The centers sit at 1, 5.4, 9.8, 14.2, 18.6 and 23 inches from the top.
Asking for a 4 inch space instead gives floor(22 / 4) + 1 = 6 buttons, and the spaces even out to 4.4 inches. A 5 inch space gives floor(22 / 5) + 1 = 5 buttons.
Placing buttons well
Even spacing works for many garments, cushions and cases, but some designs need a button at a certain place, such as the fullest part of the chest. Mark that one first, then divide the rest of the opening. The page treats the first and last positions as fixed, so run it for each section if you split the opening.
Mark each position with a pin or a fabric marker before sewing buttonholes, and check the marks against the garment while it is worn or on a form.
Related tools
The Picture Hanging Calculator uses the same idea of even spacing for frames. For other sewing numbers, see the Elastic Length Calculator, the Fabric Yardage Calculator and the Bias Tape Calculator.
Assumptions and limits
- Positions mark the center of each button.
- The first and last buttons are placed at the distances you enter.
- All the spaces between buttons are equal.
- Positions are shown to the nearest 1/16 inch for rulers, but marking more precisely is up to you.
Frequently asked questions
How do I space buttons evenly?
Subtract the distance for the first and last buttons from the length, then divide by the number of buttons minus one. Six buttons along 24 inches with 1 inch ends are 4.4 inches apart.
How far from the edge should the first button be?
It depends on the garment. Enter the distance your pattern gives. The page uses it as a fixed position and spaces the rest.
How many buttons fit if I know the space I want?
Divide the room between the first and last button by the space and round down, then add one. The page evens out the leftover room.
Does this work for buttonholes too?
Yes. Buttonholes sit opposite the buttons, so use the same positions, then adjust for the length of each buttonhole as your pattern says.