How much ribbon do I need for a bow?

A basic bow needs 4 times the loop size plus twice the tail length plus 10cm for the knot. For a 10cm loop bow with 15cm tails: (10 x 4) + (15 x 2) + 10 = 80cm per bow.

How do I calculate ribbon for trim?

Measure the total length of the edge being trimmed. Add 10% for waste, turning corners, and joining. For gathered ribbon trim, multiply by 2 for fullness.

What ribbon widths are standard?

Common widths: 3mm, 6mm, 10mm, 15mm, 25mm, 38mm. Thin ribbon (3-6mm) suits hand embroidery and delicate trims. Medium (15-25mm) for bows and sashes. Wide (38mm+) for sashes and hat trims.

How do I prevent ribbon from fraying?

Cut ribbon at an angle for a decorative finish. Seal cut ends with a flame (for synthetic ribbon only) or clear nail polish. Fold ends under when sewing into seams. Grosgrain ribbon frays less than satin.

SewCalcs

Ribbon Calculator — Ribbon Length

Work out ribbon length needed for trims, bows and decoration.

Application

Total Trim Length

Wastage %

Ribbon Price (optional)

How We Calculate This

Ribbon requirements depend on the application. Trim needs the edge length. Bows need loop, tail and knot allowances multiplied by quantity.

The formula

Trim: Length = Edge length + Wastage

Bow: Per bow = (Loop × 4) + (Tails × 2) + 10cm

Total = Base length × (1 + Wastage%)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.