How this instrument works
Criss-cross lacing — the pattern on most sneakers and dress shoes, where the lace zigzags diagonally between opposite eyelets — needs more lace than people expect, because most of its length is used by diagonal segments rather than the visible top row. Each diagonal spans both the horizontal gap between eyelet columns and the vertical gap between eyelet rows, so its true length is the hypotenuse of a right triangle, found with the Pythagorean theorem: diagonal = √(horizontal² + vertical²).
A shoe with 5 eyelet pairs has 4 gaps between rows, and because lacing alternates sides, that works out to (pairs−1) diagonal crossings per side, or 2×(pairs−1) in total — each one costing that same hypotenuse length. Add the horizontal stretch across the bottom eyelets and the free length left hanging for tying on one side, then double that whole sum to account for both mirrored sides of the lace, and you have the complete length.
This calculator covers only the basic criss-cross pattern — the one nearly every factory-laced shoe ships with. Other lacing styles, such as straight/bar lacing, starburst, or hellix patterns, route the lace differently between eyelets and need different diagonal-count formulas; a lace length calculated here won't be accurate for those alternate patterns.
- Count your eyelet pairs — one pair per row, both sides included (a typical low sneaker has 5-6 pairs; boots often have 7 or more).
- Measure horizontal spacing — the straight-line distance between two eyelets in the same row, left to right.
- Measure vertical spacing — the distance between two consecutive eyelet rows, bottom to top.
- Set free end length — how much loose lace you want hanging on each side once threaded, enough to tie your preferred knot or bow.
- Read Total lace length — the finished lace length to buy or cut, in centimeters.
Worked example — a 5-eyelet-pair sneaker
A sneaker with 5 eyelet pairs, 6 cm horizontal spacing and 2 cm vertical spacing between rows, and 15 cm of free lace wanted per side: each diagonal = √(6² + 2²) = √40 ≈ 6.325 cm. With 5 pairs there are (5−1) = 4 diagonal crossings per side, contributing 4 × 6.325 ≈ 25.30 cm.
Adding the horizontal stretch across the bottom eyelets (6 cm) and one free end (15 cm): 6 + 25.30 + 15 ≈ 46.30 cm for one side, then doubling for both sides of the lace: total = 2 × 46.30 ≈ 92.60 cm. A shoelace sold at roughly 100 cm (a common off-the-shelf length) would comfortably cover this shoe with a little to spare for the knot itself.
Questions
Why does my new shoelace always seem too long or too short?
Because shoelace packaging almost never lists eyelet count or spacing — it's sold by a rough length category (like "sneaker" or "boot") that has to fit a wide range of actual eyelet layouts. This calculator works from your shoe's actual measurements instead, so the result is sized to your specific shoe rather than a generic category.
Does this work for boots with more eyelets, or hooks at the top?
Yes for eyelet count — just enter your shoe's actual number of eyelet pairs and its spacing, and the formula scales correctly for boots with 7, 8, or more pairs. Speed hooks at the top (common on hiking boots) are still criss-crossed the same way as eyelets for this calculation, though the exact spacing at a hook row can differ slightly from the eyelet rows below it, so measure that row specifically if it looks different.
What if I want longer or shorter free ends than 15 cm?
Adjust the free end length input directly — it's added twice (once per side) to the total, so increasing it by 5 cm adds 10 cm to the total lace length. Longer free ends give more room for larger bow knots or double-wrapping around the ankle on boots; shorter free ends suit a plainer, tucked-in finish.
My shoe uses straight (bar) lacing, not criss-cross — will this give the right length?
No — straight/bar lacing routes the lace mostly horizontally across each row rather than diagonally between rows, so it uses a different, shorter formula than the criss-cross diagonal method this calculator is built around. Using this result for a straight-laced shoe will overestimate how much lace you actually need.
How do I measure eyelet spacing accurately on my own shoe?
Lay the shoe flat and measure center-to-center between two eyelet holes, not edge-to-edge — for horizontal spacing, measure between the left and right eyelet in the same row; for vertical spacing, measure between one row and the row directly above it. A cloth tape measure or a ruler laid along the shoe's tongue works well for both.