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Button Quantity Calculator

Work out button quantity instantly with clear inputs, formula shown and shareable results.

About Button Quantity Calculator

Buttons sit at both ends of the placket, so the count is the number of gaps plus one, and the actual spacing is the placket length divided by that gap count. The gaps-plus-one rule is why six buttons at 8 cm nominal spacing on a 60 cm placket actually sit 8.57 cm apart once evened out.

Formulas

Button count

buttons = round(placket length / target spacing) + 1

Even spacing

spacing = placket length / (buttons - 1)

Worked example

With the default values below, Button Quantity Calculator returns Buttons on the placket of 9. Change any input above and every figure here is recalculated in your browser.

Inputs used

Length of the button placketminimum 1 cm
60 cm
Target spacing between buttonsminimum 0.5 cm
8 cm
Spare buttons to buyminimum 0
2

Results

Buttons on the placket
9
Actual even spacing
7.50 cm
Buttonholes to work
9
Buttons to buy including spares
11

Step by step

  1. 1Values used
  2. 2Button count
  3. 3Even spacing
  4. 4Buttons on the placket= 9
  5. 5Actual even spacing= 7.50 cm
  6. 6Buttonholes to work= 9
  7. 7Buttons to buy including spares= 11

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Button Quantity figure worked out?

buttons = round(placket length / target spacing) + 1. Buttons sit at both ends of the placket, so the count is the number of gaps plus one, and the actual spacing is the placket length divided by that gap count.

Why does this matter?

The gaps-plus-one rule is why six buttons at 8 cm nominal spacing on a 60 cm placket actually sit 8.57 cm apart once evened out.

What do I need to enter?

Enter length of the button placket, target spacing between buttons, spare buttons to buy. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.

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