Estimate the lace length for regular crisscross lacing from your eyelet spacing and desired ends. You can also compare a lace you already have.

Changing units converts all populated length fields.

Count pairs, not individual holes; enter 2–50.

Between opposite eyelet centers, with the shoe comfortably tightened.

Between neighboring eyelet centers up one side. Use average spacing if it varies.

Measure from the knot center to the lace tip, not from the top eyelet.

Compare an available lace (optional)

Measure the whole lace. Leave blank to omit the comparison.

For regular crisscross eyelet lacing. Curved paths, thickness, stretch and tying can change the length used. Check with a real lace or cord.

Use positive decimals. Technical limit: 1,000,000 cm (10 km) per length.

After Calculate, these inputs are saved in this browser. Other scripts on this site may access saved values. Reset clears this calculator’s saved data.

Shoelace length formula

B = 2H + 2(P − 1)√(H² + V²)
T = B + 2E

P is the number of eyelet pairs used. H is the spacing across opposite eyelet centers, V is the spacing between adjacent eyelets up one side, and E is the desired length of each end measured from the knot center. B is the modeled path to that center; T is the total lace estimate. All lengths use the selected unit.

How to measure

  1. Count the eyelet pairs you will use with regular crisscross lacing.
  2. Measure H and V with the shoe comfortably tightened. If spacing varies, use averages; irregular eyelet spacing makes the geometric estimate less precise.
  3. Enter your desired end allowance E using the knot-center convention. Measuring from the top eyelet would use a different reference point.
  4. Optionally enter the length of your whole available lace, then select Calculate.

This model is for eyelets, not hooks or lugs, and does not include a heel-lock loop or another lacing pattern. Lace thickness, eyelet curvature, stretch and tying can affect the amount used. Test the route with a lace or cord before choosing a replacement.

Example

For 6 pairs, H = 5 cm, V = 2 cm and E = 15 cm, each diagonal is √29 cm. The modeled path B is about 63.8516 cm, and the total T is about 93.8516 cm.

An available 90 cm lace has a margin of about −3.8516 cm against that estimate. Under the same geometry, its equal ends would be (90 − 63.8516) ÷ 2 ≈ 13.0742 cm each.

Available-lace comparison

The signed margin is A − T, where A is the whole available lace length. If A is at least B, the modeled length of each equal end is (A − B) ÷ 2. If A is below B, the tool reports the shortfall before the knot center and leaves equal ends unavailable. Blank A omits this comparison.

FAQ

Does this select a lace to buy?

No. It estimates one geometric route using your measurements and end allowance; it does not choose a stocked length, predict bow size or guarantee suitability.

Can I change units?

Yes. Populated length fields convert together between centimetres, millimetres and inches. The conversion uses 1 in = 2.54 cm and 1 cm = 10 mm, retaining up to 15 significant digits. Select Calculate again to update the result.

What does a negative margin mean?

The available lace is shorter than the estimate for your entered end allowance. Comparisons use unrounded calculations; small differences use scientific notation so their direction remains visible.

Sources