Curtain Fabric Calculator

A single window 120cm wide with floor-length pencil-pleat curtains (2x fullness) needs about 4.4 metres of standard 137cm-wide fabric. The maths: width 120cm times 2x fullness equals 240cm of curtain. Standard fabric is 137cm wide so you need 2 widths joined down the middle. Multiply 2 widths by the 220cm drop, add 10% for hems and headers, and you land at roughly 4.4 metres at £15/m, or around £66 for the fabric alone.

Different heading types pull fabric quantities up or down. Eyelet and tab-top use 1.5x fullness (less material). Pinch pleats use 2.5x (more luxurious but expensive). Wave headings sit at 2x. The same window in pinch pleats needs 5.5 metres - over a metre more than pencil pleats. Always measure the pole or track width, not the window opening, because curtains overlap the frame by 15 to 20cm each side.

Three standard drops apply to most British windows. Sill-length (around 180cm from a typical pole) sits just below the windowsill - a casual look that works in kitchens and bathrooms. Floor-length (220cm from a typical pole) just brushes the floor - the safest option for living rooms and bedrooms. Below-sill or pooled lengths add 5 to 30cm extra and pool fabric on the floor for a dramatic look.

Always measure your specific window before relying on the defaults - ceiling heights vary from 220cm in older British homes to 270cm or more in modern builds and Victorian conversions. The pole or track sits 15cm above the window frame in most cases, but extending the pole higher (up to 30cm above the frame) makes the window look taller and the room look bigger. The calculator lets you enter a custom drop for those non-standard situations.

Lined curtains hang better, block more light, and last longer. Standard cotton lining costs about £6 to £8 per metre and you need roughly 95% as much lining as main fabric (lining is slightly narrower and you skip the bottom hem). For a 120cm window with floor-length pencil pleats, that is around 4.2 metres of lining at £6/m, or £25 to add to the £66 fabric cost.

Blackout lining costs £10 to £14 per metre and is essential for bedrooms facing east or street-lit pavements. Interlining (a soft middle layer) doubles the warmth and weight, costs another £4 to £8 per metre, and turns DIY curtains into a serious project that takes 6 to 10 hours per pair to make. The [fabric cost calculator](/fabric-cost-calculator) handles broader sewing projects beyond just curtains.