sewcalcs.uk
Velcro Calculator — Hook & Loop Tape
Calculate hook-and-loop tape length for closures and fastenings.
How We Calculate This
A hook-and-loop closure needs an equal length of hook tape and loop tape. For each closure the tape spans the opening, plus a little overlap, plus a fold-under at each end so the cut edges do not fray. UK haberdashers sell sew-on tape per metre with the hook and loop sides paired together, so the length you buy is the each-side figure.
The formula
Length per side = (Closure length + overlap + 2 × fold-under) × Number of closures
Buy this length of paired hook-and-loop tape (it includes both sides). The combined hook + loop figure only matters if you buy hook and loop on separate single-sided rolls.
Frequently Asked Questions
Hook-and-loop tape comes in two forms: on a roll with hook and loop side by side, or as separate hook and loop rolls. Buying separately lets you position each side independently. Both sides are needed for a closure.
Sew-on tape is most versatile and durable. Adhesive-backed tape is quick but may not withstand washing. Iron-on tape bonds with heat. For garments, always use sew-on tape for durability.
16mm for lightweight closures and small items. 20mm is the most common for garment overlaps and cushion covers. 25mm and wider for bags, equipment covers, and heavy-duty applications.
Use a standard presser foot and medium stitch length. Sew around all four edges of each piece. Use a polyester thread — cotton thread can be cut by the hooks. Round the corners to prevent peeling.
Related Calculators
Hook and Eye Calculator
Calculate hook and eye spacing and quantities for closures.
Elastic Calculator
Calculate elastic length for waistbands, cuffs and casings.
Webbing Calculator
Calculate webbing length for bag straps, belts and hardware.
Button Spacing Calculator
Calculate even button spacing and placement for garments.
Ribbon Calculator
Work out ribbon length needed for trims, bows and decoration.
Was this calculator helpful?
Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.