How far apart should roman blind folds be?

Standard fold spacing is 18-25cm. Smaller blinds suit 18-20cm folds; larger blinds look better with 22-25cm. The bottom fold is usually half the spacing of the others for a neat stack.

How many rods does a roman blind need?

The number of rods is one fewer than the number of folds. A typical window blind has 4-6 rods. The rods (dowels or flat fibreglass rods) sit in pockets on the back and keep the folds straight.

Do I need lining for a roman blind?

Lining is recommended for almost all roman blinds. It protects the face fabric from sun damage, improves the appearance from outside, adds body for neater folds, and blocks light. Use blackout lining for bedrooms.

How much roman blind tape do I need?

You need 3 rows of tape for blinds up to 120cm wide (one each side and one centre). For wider blinds, add an extra row every 40-50cm. Each tape runs the full drop of the blind plus 5cm for knotting.

SewCalcs

Roman Blind Calculator — Fabric, Rods & Tape

Calculate fabric, lining, rods and tape for roman blinds.

Finished Blind Width

Finished Blind Drop

Fold Spacing

Side Seam Allowance

Hem Allowance

Heading Allowance

Include Lining

Recommended for all roman blinds

Fabric Price (optional)

How We Calculate This

Roman blind fabric is calculated from the finished dimensions plus seam and hem allowances. Rod pockets are evenly spaced down the drop.

The formula

Cut width = Blind width + (Side seams × 2)

Cut drop = Blind drop + Hem allowance + Heading allowance

Folds = floor(Blind drop ÷ Fold spacing)

Rods = Folds - 1

Frequently Asked Questions

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Last updated: February 2026

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