How to Choose Curtains Without Getting the Sizing Wrong

What's the biggest mistake people make with curtains?

Hanging them too low and too narrow. Nine times out of ten, that is why a window looks mean and the curtains look like an afterthought. The pole goes up right on top of the window frame, the curtains are just wide enough to cover the glass, and the whole thing sits there like a stamp on a large envelope.

The fix costs nothing extra and changes everything: lift the pole and extend it past the frame on both sides. Suddenly the window looks taller, the wall looks grander, and even inexpensive curtains read as deliberate. This one move does more for a room than the fabric you eventually choose.

How high and wide should you hang curtains?

The general rule we use: hang the pole roughly halfway between the top of the window frame and the ceiling, and if the ceiling is close, take it right up to within 10–15cm of the coving. Height is what makes a window look tall and a room look generous.

For width, the pole should extend 15–25cm beyond the frame on each side. That does two jobs — it lets the curtains stack back off the glass when open, so you get the full window and full daylight, and it makes the window read wider than it is. A curtain that half-covers the glass when open is a curtain hung too narrow.

• Height: pole two-thirds to three-quarters up the wall, or 10–15cm below the ceiling in a low room.
• Width: 15–25cm past the frame each side so open curtains clear the glass entirely.
• Fullness: order fabric around 2 to 2.5 times the pole width so the curtains gather into proper folds, not flat sheets pulled tight.
• Floor to pole: measure this height, not just the window, when you buy ready-mades — that is the drop that matters.

What length should curtains be: kiss the floor or puddle?

Curtains should reach the floor. Full stop, for almost every room. Short curtains that stop on the sill or, worse, dangle awkwardly above a radiator are the fastest way to make a room look dated and a window look stunted. The only real exception is a window physically blocked by a radiator or a run of worktop beneath it.

Below floor length, you have three honest choices. The float, a whisker off the floor — around 1cm — is the crisp, practical option that clears the carpet and suits busy rooms. The kiss, where the hem just grazes the floor, is the classic tailored look and what we reach for most. The puddle, where 5–15cm of extra fabric pools on the floor, is a deliberately soft, romantic choice for a bedroom or a period drawing room — but it gathers dust and is a menace with pets, so choose it on purpose, not by accident because you bought them too long. Whatever you pick, avoid the in-between trouser-too-short length that hovers a few centimetres up; it looks like a mistake because it usually is.

How do you choose the right fabric weight?

Fabric weight decides how a curtain hangs and what it does. Light fabrics filter and float; heavy fabrics block light, insulate and hold a crisp fold. Match the weight to the room's job before you fall for a colour.

• Sheers (voile, light linen): privacy and softened daylight without darkness — lovely layered behind a heavier pair.
• Medium (cotton, mid-weight linen): the everyday all-rounder for living rooms; hangs well, not too fussy.
• Heavy (velvet, wool, lined cotton): insulation, drama and proper light control for bedrooms and draughty period rooms.
• Interlined: a middle layer added for body and blackout — this is what makes curtains feel hotel-grade and hang in fat, even folds.
• Blackout lining: essential in a bedroom, especially for early summer mornings and for children — worth it even behind a lighter face fabric.

Which curtain heading or pleat should you pick?

The heading is the bit at the top that gathers the fabric, and it quietly sets the whole tone. You do not need to memorise the catalogue, just know the four that matter.

Pencil pleat is the standard, budget-friendly gather — fine, if a little informal. Pinch pleat (also called French or triple pleat) is the tailored, structured heading that hangs in neat, permanent folds and looks the most expensive; it is our default for a smart living room or bedroom. Wave heading gives a clean, uniform S-curve on a track and suits contemporary rooms and big windows. Eyelet curtains, with metal rings threaded onto a pole, are casual and easy to draw, good for a relaxed room but too laid-back for anything formal. When in doubt, pinch pleat earns its keep.

Curtains or blinds: when does each win?

They are not rivals so much as different tools, and plenty of the best windows use both. The choice comes down to the window, the room and how much softness you want.

Blinds win where a curtain would be impractical or intrude: a small kitchen window, a bathroom, a window above a worktop, or anywhere you want to keep the sill clear and the look tidy. A Roman blind gives you fabric softness in a compact form; a shutter or a simple roller suits utility spaces. Curtains win where you want warmth, insulation, and that soft frame around a window — living rooms and bedrooms, above all. The layered move, a blind for daytime light control plus curtains for evening cosiness and dressing the window, is the one that looks properly finished. On a bay or an awkward shape, blinds inside each recess with a single curtain pair across the front often solves what neither could alone.

What sizing mistakes should you avoid?

Curtains are unforgiving of guesswork, and the common errors repeat in home after home. Sidestep these and you are most of the way there.

• Hanging too low — right on the frame instead of high up the wall, which stunts the window.
• Hanging too narrow — a pole barely wider than the glass, so open curtains block half the daylight.
• Skimping on fullness — flat, tightly stretched curtains with no folds always look cheap.
• The wrong length — sill-length in a living room, or an accidental floating-above-the-floor hover.
• Measuring the window, not the drop — always measure from the pole to the floor, since that is the length you actually need.
• Forgetting the lining — no blackout in a bedroom, or no interlining where you wanted body and warmth.

How can you see curtains in your room before buying?

Curtains are a genuinely expensive thing to get wrong — made-to-measure especially — and it is hard to judge from a fabric swatch how a colour, weight and length will sit against your walls and floor. A sample the size of a beer mat tells you very little about a three-metre drop.

Seeing them on your actual window first helps. With Decorly you upload a photo of the room and generate redesigned versions in seconds, testing curtain colours, weights and lengths against your real window, wall colour and floor before you order. It is a quick way to settle the look, then measure and buy with confidence.

Frequently asked questions