KDS London Interiors · London

Curtain Fabric Calculator: How Much Fabric Do I Need?

By the KDS London team Updated 2026 London interiors

Made-to-measure curtains are priced by the metre, so the number that matters is how much fabric your window actually swallows once you allow for fullness, hems and a repeating pattern. Enter your measurements below and we will work out the fabric drops, total metres and rough cost. The figure most people underestimate is fullness: a curtain that looks generous needs roughly twice the flat fabric of the track it hangs from.

Your window and curtains

Measurements

Style and fabric

We add 25 cm to each drop for the heading turnover and a double bottom hem, then round the number of fabric drops (widths) up to a whole number because you cannot buy part of a width. With a patterned fabric, every drop is rounded up to the next full repeat so the pattern lines up across the join, which is where a bold print quietly eats an extra metre or two.

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