# Curtain lining calculator Curtain lining is bought separately from the face fabric and calculated differently: it is plain, so no pattern repeat has to be matched, it comes on a narrower roll — 137 cm is the UK standard — and it is cut short of the face fabric so it cannot show below the hem. Because the roll is narrower, a curtain that took two widths of face fabric can need three of lining. The calculator below takes the flat width your curtains need and solves it again on the lining roll, showing every allowance. Source: https://fabricmeasure.com/calculators/curtain-lining-calculator/ Last updated: 2026-08-20 (method v1) Published by FabricMeasure. --- ## The formula ``` flat width per curtain = (track width + returns + overlap) x fullness / curtains lining widths per curtain = ceil so that W x lining width - 2 x side hem - (W-1) x 2 x seam >= flat width per curtain lining cut length = finished drop - shortfall + heading allowance + lining hem total = widths per curtain x curtains x cut length, ROUNDED UP to the cut increment ``` Lining is plain, so no pattern repeat is matched and no cloth is lost rounding a cut up to the next whole repeat. It is cut SHORT of the face fabric so it cannot show below the hem. Side hems are charged to the two OUTER edges only; every join between widths costs two seam allowances instead. ## Defaults - Lining width: 137 cm (the UK standard; narrower than most furnishing fabric) - Heading allowance: 15 cm (the same as the face fabric) - Lining hem: 10 cm, single-turned - Side hem: 5 cm per outer edge - Seam allowance: 1.5 cm - Shortfall below the face hem: 2.5 cm - Cut increment: Nearest 10 cm (Most UK and European shops cut roll goods to the nearest 10 cm.) Every one of these is an editable input on the page. ## Worked example 200 cm track, 220 cm drop, a pair at 2x fullness, standard 137 cm lining. | Step | Working | Result | | --- | --- | --- | | Lining widths per curtain | 200 cm needed ÷ 137 cm lining, allowing 10 cm of side hems | 2 widths | | Lining cut length | 220 cm drop − 2.5 cm shortfall + 15 cm heading + 10 cm hem | 242.5 cm | | Lining required | 4 cuts × 242.5 cm | 970 cm | Buy: 9.7 m ## Not modelled - Interlining: a third layer, its own roll width, no side hems because it is enclosed. - Detachable linings: made to their own finished width, not solved from the face flat width. - Patterned lining: would need repeat matching, which this does not do. ## Common questions ### How much lining do I need for a pair of curtains? The same flat width as the face fabric, solved again on the lining roll. Because standard UK lining is 137 cm and much furnishing fabric is 140 cm, the lining sometimes needs an extra width per curtain that the face fabric did not. The length is slightly less, because lining is cut short of the hem. ### Why is the lining cut shorter than the curtain? So it cannot peep below the hem when the curtain hangs. A shortfall of about 2.5 cm is normal — enough that the lining stays hidden as the face fabric settles and drops over the first few weeks, and not so much that the lining pulls the hem up. ### Can I use the same fabric width for lining as for the curtains? Only if that is what your supplier sells. Curtain lining is woven for the job at 137 cm and is not usually offered in the widths furnishing fabric comes in. Enter what your roll actually measures rather than assuming it matches the face fabric — the width is what decides the number of widths. ### Should the lining seams line up with the face fabric seams? Where you can, yes. Two sets of joins in different places show as ridges in raking light, particularly through a pale face fabric. Where the widths do not divide the same way — which is exactly what happens when the two rolls are different widths — place the lining seams as close to the face seams as the cloth allows. ### Does interlining change the calculation? Yes, and this tool does not model it. Interlining is a third layer between face and lining, cut to its own width and usually without side hems because it is enclosed. It also adds bulk that changes how much the heading consumes. Calculate it separately against its own roll width. ## Related tools - [Curtain fabric calculator](https://fabricmeasure.com/calculators/curtain-fabric-calculator/): Track width, drop, fullness and pattern repeat in; metres or yards to buy out, with every allowance adjustable. - [Curtain fullness calculator](https://fabricmeasure.com/calculators/curtain-fullness-calculator/): How many widths each curtain needs at the fullness you want — and what whole widths really gather to. - [Curtain heading types](https://fabricmeasure.com/charts/curtain-heading-types/): Five headings compared on fullness, allowance and what they cost in cloth. - [Fabric width chart](https://fabricmeasure.com/charts/fabric-width-chart/): Standard roll widths in both systems, and the gap between the label and the cloth. - [Pattern repeat calculator](https://fabricmeasure.com/calculators/pattern-repeat-calculator/): The cut length a repeat forces, what is trimmed from every piece, and what matching the design costs.