How this calculator works
A shoelace follows the eyelets in straight segments and diagonals, so its length is the sum of those segments plus the two free ends used for the bow. In criss-cross lacing the lace crosses the bottom pair horizontally, then makes two diagonal runs at every level above, one on top and one underneath. Each diagonal is the square root of the horizontal gap squared plus the vertical spacing squared. Straight-bar lacing replaces the diagonals with horizontal bars and vertical runs up the sides, which uses less lace. The table compares the patterns with the same spacings.
Formula
criss-cross and over-under: length = gap + 2 x (pairs - 1) x square root(gap squared + spacing squared) + 2 x free end. straight bar: length = pairs x gap + 2 x (pairs - 1) x spacing + 2 x free end.
Worked example
Six pairs with a 2.5 cm gap, 2 cm spacing and 30 cm ends in criss-cross: the diagonal is 3.20 cm, so the length is 2.5 + 2 x 5 x 3.20 + 60 = 94.5 cm. The same shoe in straight bar lacing is 6 x 2.5 + 2 x 5 x 2 + 60 = 95 cm.
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Frequently asked questions
How long should the free ends be?
About 25 to 30 cm on each side gives enough lace to tie a bow comfortably. If you like a large double knot or have wide shoes, use 35 cm. Too little free end is the most common reason a correctly measured lace is hard to tie.
Why do the lacing patterns differ in length?
They use different paths. Criss-cross has two diagonals per level, and each diagonal is longer than the vertical or horizontal run it replaces. Straight bar uses horizontal bars and vertical side runs, so it usually needs less lace for the same shoe.
Does this include the eyelet diameter?
No. The calculation treats each eyelet as a point. Real eyelets add a small amount for the turn through the hole and for lace thickness, typically a few centimetres over the whole lace. Rounding up to the next length the shop sells covers that.
What about sawtooth or other patterns?
This page covers the three patterns with well-established length formulas. Sawtooth, train track, starburst and the helix patterns need more lace, and their exact lengths depend on the path, so use the pattern guide from the lace maker rather than a simple formula.