Fabric Guides  ·  Curtain Making

Curtain Math Made Easy:
How Much Fabric Do I Actually Need?

Published 21 April 2026 · 7 min read · By Discount Fabrics Ltd

"I'll just guess how much I need." Famous last words — followed by a frantic re-order that doesn't quite match the dye lot.

Ordering curtain fabric feels harder than it should be. Too little and you're scrambling. Too much and you've wasted money. The good news? There's a simple formula — and once you know it, you'll never second-guess an order again.

This guide breaks it down window by window, fabric type by fabric type. By the end, you'll know your exact metre count before you even open the shop.

×2.5
Minimum fullness ratio for standard curtains
+20cm
Always add for hem & heading allowance
+1
Extra pattern repeat to buy — every single time
Beautiful curtains hanging in a bright UK home interior
Step One

The Formula Every UK Home Sewer Needs

Whether you're dressing a bay window or a single sash, the calculation is always the same. Measure once, order right — no guesswork, no drama.

The Standard Curtain Fabric Formula

Total Fabric (m) = (Track Width × Fullness) ÷ Fabric Width × Number of drops + Hem & Heading (20–30cm per drop) + Pattern Repeat (1 full repeat extra per drop)

Fullness guide: Pencil pleat = ×2.5  |  Eyelet = ×2  |  Pinch pleat = ×2.5  |  Tab top = ×1.5
Most curtain fabric from Discount Fabrics Ltd is 137–140cm wide — use 137cm in your calculations to stay safe.

UK pro tip: Always round up to the nearest half metre when ordering. If your calculation gives you 4.3m — order 4.5m. The small cost is nothing compared to a mismatched top-up order weeks later.

Step by Step

How to Measure Your Window in 4 Steps

01

Measure the Track or Pole Width

Measure the full length of your track or pole — not the window frame. Curtains need to extend 15–20cm past the frame on each side to block light properly.

Add 15–20cm each side of the frame
02

Measure the Drop

Measure from the top of the track down to where you want the curtain to end. Floor-length: stop 1cm above the floor. Add 15cm at the top (heading) and 10–15cm at the bottom (hem).

Always measure from the track, not the window
03

Apply the Fullness Multiplier

Flat fabric looks flat. Multiply your track width by your chosen fullness ratio. Divide by the fabric width to find your number of widths. Always round up — never down.

Round widths up — never down
04

Add the Pattern Repeat

The step most beginners skip — and regret. If your fabric has a pattern repeat (e.g. 32cm), every cut length must start at the same point. Add one full repeat per width you're cutting.

Check the product page for repeat size

Worked Example: A Standard UK Living Room Window

  • Track width: 160cm  →  ×2.5 fullness = 400cm of fabric width needed
  • Fabric is 137cm wide  →  400 ÷ 137 = 2.9 → round up to 3 widths
  • Drop: 230cm + 30cm allowance = 260cm  →  3 × 2.6m = 7.8m
  • Pattern repeat: 28cm  →  3 × 0.28m = 0.84m → round up to +1m
  • Total order: 9 metres — rounded up from 8.64m for peace of mind
Quick Reference

Heading Style Cheat Sheet

Not sure which heading type you're making? Here's how they differ — and what that means for your fabric order.

Heading StyleFullness NeededBest Fabric TypeDifficulty
Eyelet / Ring Top×2 – ×2.5Cotton, linen, velvetBeginner
Pencil Pleat×2.5 – ×3Most fabrics — very versatileBeginner
Pinch Pleat×2 – ×2.5Structured cotton, linenIntermediate
Tab Top×1.5 – ×2Lighter fabrics — voile, cottonBeginner
Wave / S-Fold×2 – ×2.3Linen, cotton, sheer blendsIntermediate
Goblet Pleat×2.5Medium–heavyweight, velvet idealAdvanced
Choosing Your Fabric

Which Curtain Fabric Is Right for Your Room?

🪟

Cotton & Polycotton

The most versatile choice. Holds structure well, easy to sew, and comes in every colour and print imaginable. Perfect for bedrooms and living rooms year-round.

Width: typically 137–140cm
🌿

Linen & Linen Blends

The relaxed, natural look that never dates. Linen drapes beautifully in a wave heading and softens with washing. Best for living rooms and kitchens with natural light.

Allow extra: linen shrinks ~3–5%
🌙

Velvet & Chenille

Heavyweight luxury. Adds warmth, blocks light, and creates true drama. Perfect for formal sitting rooms and bedrooms. Use a pinch or goblet pleat to show it off.

Cut all drops in the same direction
☀️

Voile & Sheer

Layer over a blackout lining or use as a standalone privacy screen. Lightweight sheers need even more fullness — go up to ×3 for a lush gathered look.

Fullness: ×2.5–3 recommended

Don't forget lining. An interlining protects your fabric from UV fading, improves drape, and adds insulation. For blackout lining, measure exactly the same as your curtain fabric — it cuts to the same dimensions.

Shop the Range

Top Picks for Curtain Making

Best Seller Cotton curtain fabric plain and printed

Cotton Curtain Fabric — Plain & Printed

Medium-weight, pre-shrunk, available in an extensive colour range. Works with every heading type.

Shop Curtain Fabric →
New In Linen curtain fabric

Linen & Linen-Look Fabrics

Natural texture, beautiful drape. Washed and pre-treated for curtain use — no surprise shrinkage.

Explore Linen →
For Beginners Curtain tape rings and accessories

Curtain Tape, Rings & Accessories

Eyelet tape, pencil pleat tape, curtain hooks, and weights — everything alongside your fabric.

Shop Accessories →
Liberty Liberty London print fabrics

Liberty London Print Fabrics

Statement curtains deserve statement fabric. Use our Liberty prints for a single accent window that transforms a room.

View New Arrivals →
You've done the maths. Now comes the fun part.

Ready to Order Your Curtain Fabric?

Browse our full curtain fabric range — over 100 options by the metre, delivered to your door across the UK. Not sure which is right for your room? Our team is always happy to help.

5%

Off your first order
with newsletter signup

Subscribe Free