Button Spacing Calculator

How do you space buttons evenly?

Uneven button spacing is instantly visible, even to people who cannot say why a shirt looks wrong, because the eye is excellent at spotting an irregular rhythm. The classic method is simple: divide the placket length by the number of buttons plus one, and that gives the spacing between buttons and the margins at both ends. The plus one is the key, because it creates an equal gap above the first button and below the last button, so the buttons sit in a balanced row rather than crowding one end. The calculator on this page applies that formula: a forty-centimetre placket with five buttons gives six point seven centimetres between buttons, with the first button six point seven centimetres from the top edge.

Why not simply divide by the number of buttons? Because that places a button exactly at each end of the placket, which looks cramped and leaves no room for the top button to sit below the collar or the bottom button to sit above the hem. Real garments need breathing room at both ends, and the plus-one method provides it automatically. If your placket has a collar or a waistband, measure the placket between the points where buttons can actually sit, not the full garment length, and exclude any area where a button would be hidden or unwearable. For a shirt, the top button typically sits just below the collar stand, and the bottom button sits a few centimetres above the hem.

How many buttons should a garment have?

Button count follows garment type and spacing convention more than arithmetic. Shirts typically space buttons eight to ten centimetres apart, which gives a relaxed, classic look, while blouses and dresses often use six to eight centimetres for a neater appearance. Cardigans vary widely, from chunky buttons ten or more centimetres apart to fine buttons every five centimetres. If you know your desired spacing, work backwards: divide the placket length by the desired spacing, subtract one, and round to the nearest whole number of buttons. A sixty-centimetre cardigan at nine-centimetre spacing needs about six buttons, while the same cardigan at seven centimetres needs about eight. When the result falls between counts, choose the count that gives spacing closest to your target.

Marking buttons accurately

Accurate marking matters as much as accurate arithmetic, because a millimetre of drift per button compounds down the placket. Mark on the button side of the garment, using tailor's chalk or a water-soluble pen, and measure from a fixed edge, not from the previous button, so errors do not accumulate. A button gauge, a strip of card marked with your spacing, speeds the job and keeps it consistent, and it is worth making one for any garment with more than a few buttons. Mark buttonholes on the overlapping side and buttons on the underlapping side, and double-check that the two sides align when the garment is closed, because a buttonhole row and a button row marked from different edges will not meet.

Buttonholes deserve the same care as spacing. A buttonhole should be slightly longer than the button's diameter plus its thickness: a flat button needs a hole about its diameter, while a thick or domed button needs a longer hole to pass through. Test buttonhole length on a scrap of the same fabric with the same interfacing, because a hole that is too tight strains the fabric and a hole that is too loose lets the button slip out. Position buttonholes horizontally on shirts and blouses, so the button sits at the outer end of the hole and the garment pulls against the inner end, and vertically on bands where horizontal holes would gap. Reinforce buttonholes on fine fabrics with interfacing, and use a stabiliser under stretch fabrics.

Special cases: bust points, waistbands, and cuffs

Even spacing is the default, but some garments break it deliberately. On a fitted blouse or dress, a button placed exactly at the bust point prevents gaping, and spacing is then adjusted around that fixed point, with even gaps above and below it rather than across the whole placket. Waistbands and cuffs often use a single button, centred, or a pair, and those positions follow function rather than spacing formulas. Double-breasted garments need two parallel rows, each spaced evenly, with the rows far enough apart that the overlap lies flat. For children's clothes, fewer, larger buttons are easier to fasten and safer than many small ones, and for coats, spacing widens to suit larger buttons and thicker fabric.

Button size interacts with spacing in a way that is easy to overlook. Large buttons need more room to look balanced, so a placket with chunky twenty-five-millimetre buttons looks crowded at six-centimetre spacing, while the same spacing suits fifteen-millimetre buttons perfectly. As a guide, spacing should be at least three times the button diameter for a relaxed look, and at least twice for a close, tailored look. Shank buttons, which stand off the fabric on a small loop, need buttonholes slightly longer than flat buttons of the same diameter, and they suit thicker fabrics where a flat button would sit too tightly. Four-hole buttons are sewn with a thread shank on thick fabrics, so the button stands proud and the layers close without strain.

Sewing buttons that stay on

A well-spaced button that falls off is still a failure, so sew buttons securely. Use thread matched to the fabric, doubled for strength, and sew through each hole several times, building a small thread shank by wrapping thread around the stitches under the button before knotting. Knot on the underside, and for garments that will be washed often, consider a small backing button on the inside, which spreads the strain and prevents the button tearing through the fabric. Check button alignment after sewing the first two, because it is easier to move one button than to re-sew a whole row, and press the placket carefully at the end, avoiding direct heat on plastic buttons.

• Spacing = placket length divided by (buttons + 1).
• Measure from a fixed edge, not from the previous button.
• Test buttonhole length on a scrap first.
• Fix one button at the bust point to prevent gaping, then space around it.
• Spacing should be at least twice the button diameter.

Even buttons are a small detail that lifts a whole garment. Use the calculator above to get your spacing, mark carefully from a fixed edge, and sew buttons that sit in a perfect, even row.

Buttonholes on tricky fabrics

Buttonholes behave differently on every fabric, and the tricky ones deserve a test before you commit to the garment. On stretch knits, stabilise the placket with fusible interfacing and sew a test buttonhole on a doubled scrap, because an unstabilised knit buttonhole stretches out of shape and gaps. On velvet and pile fabrics, use a corded buttonhole or a bound buttonhole, which looks cleaner than a standard stitched hole crushed into pile. On leather and faux leather, a bound buttonhole or a simple slit with a snap is often better than a stitched buttonhole, which perforates and weakens the material. On sheer fabrics, use a fine needle, a stabiliser that tears away cleanly, and a smaller stitch density, testing first, because a puckered buttonhole on chiffon cannot be unpicked invisibly.