What size curtains do I need? UK sizes, worked out for your window

Type your window's width and height, the height of the sill and of the ceiling, and choose the length and the heading (the way the top of the curtain gathers). The calculator gives the pole's length and height, the UK ready-made pair to buy, and the size to order made to measure. Switch to inches for US sizes.

The formula

Every curtain size comes from four measurements, in this order. Curtains are sized to the pole, so work out the pole first.

Fullness is how much fabric there is for the pole: both curtains together, laid flat, divided by the pole's length. Dunelm calls 2× its standard gather and 2.5× its luxury gather. Tab tops look best at about 1.5×, because they stack flatter.

For a 120 cm window, 90 cm off the floor and 115 cm tall, in a room 2.4 m high: the pole is 120 + 40 = 160 cm long. The window's top is at 205 cm, so the pole goes at least at 220 cm, and two thirds of the way to the ceiling is 228 cm. A 229 cm eyelet drop ending 1 cm above the floor puts the pole's top at 230 cm, so that is the height. Each curtain needs 160 × 2 ÷ 2 = 160 cm: buy the 168 cm width.

Which ready-made width

UK ready-made curtains come in pairs, and the width on the pack is for one curtain, laid flat. Here are common window widths, worked out with the formula above.

The shops' own charts do not agree on how full a pair should be. Dunelm puts a pair of 168 cm curtains on a pole of 168–228 cm. Next puts its 168 cm eyelets on a pole of 210–295 cm, which hangs much flatter. If you like deep folds, follow the formula; if you like a flat, modern look, use 1.5×.

Which drop

The drop is fixed on a ready-made pair, so it decides where the pole goes. Add the drop to the height of the hem, and that is the top of the pole for eyelet and tab top curtains. These are the same numbers as in our guide to how high to hang curtains, with the sill at 90 cm:

If no drop lands between 15 cm above the window and the ceiling, buy the next drop up and take up the hems, or have the curtains made to measure. The calculator tells you by how much.

How to measure for curtains

1. The window: its width across the frame, its height from the sill to the top of the frame, and the height of the sill from the floor. Use a metal tape: it does not stretch.
2. The ceiling: from the floor to the ceiling, above the window. Note any coving or a beam.
3. The pole: if one is up, measure its length without the finials, and use that instead of the window. Next asks for the pole or track size, not a curtain size, when you order made to measure.
4. The drop: from the top of the pole for eyelet and tab top curtains, from the eye of the ring for pencil pleats on a pole, and from the top of a track. Measure down to where the hem will end.
5. A radiator: if one sits under the window, Dunelm suggests ending the curtains 3 cm above it, so its heat comes into the room.

Heading, fullness and stack

The heading changes three things: how full the curtains should be, where the drop starts and how deep the curtains stack when they are open.

Eyelet and tab top curtains need a pole: the pole runs through them. On a track, choose pencil pleat curtains.

Five mistakes

1. Measuring the window, not the pole. Ready-made widths are matched to the pole. A pair sized to a 120 cm window is too narrow for the 160 cm pole it needs.
2. Reading the pack as the pair's width. "168 × 229 cm" is one curtain. The pair is twice that much fabric.
3. Too little fullness. At under 1.5×, curtains look stretched when shut, and gaps open at the edges.
4. Curtains 5–10 cm off the floor. They look like a mistake. End them 1 cm above the floor, at the sill, or 15 cm below it.
5. Fixing the pole first. Ready-made drops are fixed, so the curtains decide the pole's height. Choose them together, then drill.

The height rules are in more detail in how high to hang curtains. To make a small room look larger with the same curtains, see how to make a room look bigger. Renting? Check the tenancy before you drill: how to decorate a rented flat covers what you can change. Hanging art on the same wall? The picture height calculator gives the hook height.

Hang the curtains in your room before you drill

Snuug, the iPhone room app, rebuilds your room in 3D from one slow walk round it, to within about 3% of its real size in our tests of ten homes.

Try the pole 10 cm higher, the curtains to the floor or to the sill, and a pair two shades darker than the walls, all on your own window. Paint the walls before you buy a tin, paste a shop link and see the curtains in your room, and move every piece in 5 cm steps. Members get a Room Analysis that checks rules like these in centimetres, with a plan that starts with the free fixes. Our team checks every room by hand, and your first room is free.

Questions

What size curtains do I need for a 120 cm window?

A pole of about 160 cm (the window plus 20 cm each side), then a pair of 168 cm (66 in) wide curtains. For eyelets to the floor in a 2.4 m room, fit the pole's top at 230 cm and buy the 229 cm (90 in) drop. To the sill, with the sill at 90 cm, a 137 cm drop puts the pole's top at 228 cm.

Are curtain sizes for one curtain or the pair?

For one curtain. A pair of 168 × 229 cm curtains is two curtains, each 168 cm wide laid flat and 229 cm long. Together they are 336 cm of fabric, which gathers to fit a pole of about 160 cm.

What width curtains do I need for a 200 cm pole?

For the standard 2× gather, each curtain about 200 cm wide, so the 229 cm (90 in) width. At 1.5×, for a flatter look or tab tops, the 168 cm width is enough. Shops' own ranges differ: Next puts its 228 cm eyelets on poles of 295–385 cm, which is a flat 1.2–1.5×.

How do I measure the drop for eyelet curtains?

From the top of the pole down to where the hem should end: 1 cm above the floor, 1 cm above the sill, or 15 cm below the sill. Dunelm and Next both measure eyelets and tab tops from the top of the pole. For pencil pleats, measure from the eye of the ring, or from the top of a track.

What are the standard curtain sizes in the UK?

Widths of 117, 168 and 229 cm (46, 66, 90 in) and drops of 137, 183 and 229 cm (54, 72, 90 in), each curtain, sold in pairs. Some ranges add a 274 cm (108 in) drop, and Dunelm sells a 284 cm (112 in) width online in some ranges. Next's eyelets come 135, 168 and 228 cm wide.

Should curtains be wider than the window?

Yes. The pole runs 15–20 cm past each side so the open curtains stack on the wall, not over the glass, and each curtain is about as wide as the pole. A pair sized to the window covers its edges when open and leaves a gap when shut.

Editorial notes

Written by the Snuug team and checked on 1 November 2026. A number with no source beside it is a designers' rule of thumb, not a study.

1. Dunelm, How to measure for curtains (widths 117, 168, 228 cm; 2× standard and 2.5× luxury gather; hems 1 cm above the floor or sill, 15 cm below the sill, 2–7 cm puddle; window + 40 cm), read 31 Oct 2026
2. Dunelm, Curtains measuring guide (PDF, undated: tab top 1.5× the pole; where each heading's drop is measured from; 3 cm above a radiator), read 31 Oct 2026
3. Next, Living room help: curtain sizes (eyelet 135, 168, 228 cm for poles of 150–210, 210–295, 295–385 cm; drops 137, 183, 229 cm), read 31 Oct 2026
4. John Lewis, Hidcote Weave lined eyelet curtains (W167 and W228 by 137, 182, 228 and 274 cm; which pole each width fits), read 31 Oct 2026
5. Blinds Direct, How to measure for curtains (ready-made 117, 168, 229 cm wide by 137, 183, 229 cm drop), checked 31 Oct 2026
6. Dunelm Ireland (10 Nov 2018), How to put up a curtain pole (at least 15 cm above the window)
7. Havenly (Clark, 3 Jun 2025, updated 10 Jun 2026), How to hang curtains like an interior designer (two thirds of the way to the ceiling)
8. Argos, Curtain pole buying guide (15–20 cm each side). The page refused our fetch; figure from search summaries, checked 31 Oct 2026
9. Poles and Blinds, Extra long curtain poles guide (25–30 cm each side for heavy curtains). The page refused our fetch; figures from search summaries, checked 31 Oct 2026
10. Direct Fabrics, Understanding curtain stacking (about 15 cm per fabric width for eyelet, 25 cm for pencil pleat). The page refused our fetch; figures from search summaries, checked 31 Oct 2026
11. Terry's Fabrics, A guide to curtain fullness (eyelets at least 1.75×, up to 2×). Figure from search summaries, checked 31 Oct 2026

Use this from an AI assistant

This answer as JSON, or as one paragraph with format=text: https://snuug.app/api/v1/tools/curtain-size

MCP server: https://snuug.app/mcp · OpenAPI · llms.txt. Every rule cites its source.