The numbers

What fits where

If your ceiling is the common 2,400mm found in many UK flats and post-war houses, a 229cm drop is the useful one for floor-length curtains. Fit the pole or track measuring point at 2,300mm and the hem should finish 10mm above the floor. That gives a clean float. It also keeps fabric away from slightly dodgy skirting boards and makes vacuuming less of a performance.

In a Victorian terrace lounge with a 3,500mm by 4,200mm footprint, I’d usually put the pole 100-150mm above the window frame if there is wall space. If the frame top is 2,050mm and the ceiling is 2,400mm, placing the pole at 2,250mm gives you 150mm of breathing room above the frame and makes a 229cm curtain puddle by roughly 40mm. That can look deliberate if the fabric is soft. With stiff thermal lining, it can kick out at the corners.

For a 2,700mm ceiling, common in some Manchester new-builds and converted flats, 229cm curtains normally look mean unless the window is short or you are deliberately stopping at the sill. A pole at 2,600mm needs a 2,590mm drop for a 10mm float. The nearest common long ready-made drop is 274cm, so budget time for hemming or accept a 140-150mm puddle.

Watch alcoves and radiators. If a radiator projects 120mm from the wall and the pole projection is only 90mm, thermal curtains will sit on the radiator rather than in front of it. That wastes the lining. If a BS 1363 plug socket sits 80-100mm above the skirting at the window side, a heavy puddle may hide it completely, which is irritating in a home office corner.

Trade-offs in the data

Floating curtains are the least dramatic option, but they are the most forgiving in family rooms, rented flats and bedrooms where you open the window daily. A 10-15mm gap reads as intentional; a 35mm gap reads as a measuring miss. The risk is shrinkage after cleaning, particularly with cotton-rich face fabric or separate lining, so measure after deciding how the curtains will be cleaned.

Puddling gives the taller, softer look, especially under 2,700mm ceilings where 274cm drops have fabric to spare. The downside is dirt. The fabric sits on the floor, catches pet hair, and can drag if the pole is even 20mm lower than planned. Thermal lining makes that worse because the curtain has more body and less collapse.

Sill length is practical above desks, kitchen units and radiators. It is also the weakest option for heat retention because the lower edge does not seal the cold fall from the glass. If you are buying for a draughty bay, start with floor length and only retreat to sill length when furniture or a radiator makes the full drop impossible.

Pole height: the 100mm mistake

The biggest measuring error I see is using the ceiling height as the curtain length. A 2,400mm room does not take a 240cm curtain unless the track is nearly at the ceiling and you want fabric on the floor. You measure from the curtain’s hanging point: top of the track glider for tracks, the eye of the ring for pencil pleat, or the top of the pole for many eyelet curtains. Eyelets are especially sneaky because the fabric rises above the pole; two curtains sold at the same 229cm drop can finish differently once hung.

For most rooms, set the pole 100-150mm above the frame and extend it 150-300mm beyond each side of the window. Wider is better for daylight because the curtain stack parks on the wall rather than over the glass. The caveat is wall strength. Old plaster over brick can take decent fixings, but crumbly plasterboard needs the right anchors, and heavy thermal curtains need bracket load data. The supplied catalogue excerpt has no pole capacity figures, so that check has to happen at product level.

FAQs

What curtain length do I need for a 2.4m UK ceiling?

For a 2.4m ceiling, a 229cm curtain drop usually works for floor-length curtains if the pole or track measuring point is about 2,300mm high. That gives a neat 10mm float above the floor.

Measure from the actual hanging point, not from the ceiling. If your pole is lower than 2,300mm, the same 229cm curtain will touch or puddle.

What curtain length do I need for a 2.7m ceiling?

For a 2.7m ceiling, a pole at 2,600mm needs roughly a 259cm finished drop for a 10mm float. A common 274cm ready-made curtain will normally need shortening or it will puddle.

If you like a 70-100mm puddle, 274cm can work well, but only after checking your exact pole height and floor level.

Should UK curtains float or puddle on the floor?

A 10-15mm float is the most practical finish for everyday UK homes, especially rented flats and rooms with radiators or pets. A puddle suits formal rooms but needs more cleaning and more accurate pole placement.

For thermal curtains, a small float or a light touch at the floor is often better than a deep puddle because lined fabric can kick out rather than fall softly.

How high above the window should a curtain pole be?

Put the curtain pole 100-150mm above the window frame where wall space allows. In taller rooms, placing it closer to the ceiling can make the window look larger, but it changes the drop you need.

Also extend the pole 150-300mm past each side of the window so the curtain stack clears more glass.

Do thermal lined curtains need a different length?

Thermal lined curtains do not automatically need a different length, but their extra bulk changes how they hang. They are less forgiving with puddles and need enough pole projection to clear radiators and deep sills.

Check bracket load ratings before fitting them. The catalogue excerpt used here did not include curtain weights or pole capacity data.

Can curtains sit over a radiator?

Curtains can sit over a radiator, but it is usually a poor setup for thermal performance. Heat gets trapped behind the fabric instead of moving into the room.

If the radiator is under the window, consider sill length, a short apron finish, or a pole projection that lets the curtain hang in front without resting on the radiator.

Final measure

If your room is 2,400mm high, shortlist 229cm drops and decide between a 10mm float or a light puddle by moving the pole between about 2,250mm and 2,300mm. If your room is 2,700mm high, shortlist 274cm drops, then plan for hemming unless you genuinely want pooling fabric. For thermal lining, prioritise bracket strength, radiator clearance and a finish you can keep clean.