RandoziCurtain Fabric Calculator
Work out how many widths of fabric a curtain needs and how much to buy, including hems and pattern matching.
Fabric to buy
7.5 m
3 widths × 250 cm
Fabric widths
3
Cut length each
250 cm
Width after fullness
400 cm
How it works
- Choose metric (cm) or imperial (inches) and enter the width to cover and the finished curtain height.
- Pick the fullness: about 1.5 for a light gather, 2 for a classic look, 2.5 or more for sheers.
- Enter the total head and bottom hem allowance, the side allowance per edge, and the fabric width from the bolt label.
- For a patterned fabric enter the pattern repeat. Read the number of widths and the total length to buy.
What people use it for
Making your own curtains
Buy the right amount of fabric the first time instead of guessing at the shop.
Comparing fabrics
See how a narrower or wider bolt changes how many widths and how much fabric you need.
Patterned and striped fabrics
Include the pattern repeat so every width lines up with the next.
Questions
- How is the number of fabric widths calculated?
- Width to cover = window width × fullness. Usable width per fabric width = fabric width − 2 × side allowance. Widths = width to cover ÷ usable width, rounded up to a whole number.
- How is the length per width worked out?
- Cut length = finished height + hem allowance. With a pattern repeat, the cut length is rounded up to the next multiple of the repeat so the pattern matches across seams. Total to buy = widths × cut length.
- Is this for one curtain or a pair?
- It covers the total width you enter. For a pair, enter the full width of the rail; you can then split the widths between the two panels. Add a little extra for shrinkage if the fabric is washable cotton or linen.