The short answer: fix the pole or track first and measure from it, not from the window. Multiply its width by 2 to 2.5 for pencil or pinch pleats (1.5 to 2 for eyelets). Measure the drop in three places and use the shortest, finishing floor length curtains 1 to 2 cm above the floor. For a bay, measure the track run along every face. For a tall window, plan for weight in the hem, because a long curtain that is too light will not hang straight.
Most measuring guides are written for a flat, standard window in a modern room. The windows we are asked to dress are rarely like that. We have made curtains for the tall Georgian openings of a five star Mayfair hotel, for the irregular openings of a Victorian magistrates' court converted into a Shoreditch hotel, and for stone terraces a few streets from our Shipley studio. The method is the same every time. The allowances are not.
You will need a metal tape measure (fabric tapes stretch), a notebook, steps, and ideally a second person for anything tall.
The Method in Six Steps
- Choose the hardware and the heading first. A pole or a track, pencil pleat or wave, eyelet or pinch pleat: each uses fabric differently and each starts the drop from a different point.
- Fix the hardware before you measure. Every figure comes from where it hangs. If it is not up yet, mark the position.
- Place it generously. Many designers hang the pole or track well above the frame to lift the window, with 10 to 15 cm above the frame as a minimum, and extend it 15 to 30 cm beyond each side so the curtains stack back clear of the glass. Heavy, interlined curtains need more stack back than light ones.
- Measure the width of the hardware, between the finials for a pole, or the full length of a track, and multiply by the fullness (see below).
- Measure the drop from where the curtain hangs, which differs by heading (see below), to where you want it to finish.
- Measure the drop in three places, at the left, middle and right, and use the shortest for a floor length curtain. Floors in older houses are rarely level.
How Much Fullness for Each Heading?
| Heading | Typical fullness | The look |
|---|---|---|
| Pencil pleat | 2 to 2.5 times the pole or track width | Classic, even, closely gathered folds |
| Double or triple pinch pleat | 2 to 2.5 times | Tailored and formal, with defined pleats |
| Wave (also called S fold) | Around 2 times, on a track | A clean, continuous wave |
| Eyelet | 1.5 to 2 times | Relaxed and contemporary, with wide soft folds |
Below 2 times with a pleated heading, curtains look thin however good the fabric is.
Where the Drop Starts
- Eyelets on a pole: from the top of the pole. The fabric stands about 3 cm above it.
- Pleats on rings: from the underside of the ring if you want the rings to show, or from the top of the ring if the heading should cover them.
- A track: from the glider or hook that carries the curtain, not from the ceiling or the top of the track.
- Pleated headings generally: the drop is the eye drop plus the height of the heading.
Finished Length
| Style | Where it finishes | Best for |
|---|---|---|
| Sill length | 1 to 2 cm above the sill | Kitchens, bathrooms, and windows with furniture beneath |
| Below the sill | 10 to 15 cm below the sill | Covering a sill and a radiator without reaching the floor |
| Floor length (hover) | 1 to 2 cm above the floor | Most living rooms and bedrooms |
| Break or puddle | Rests 3 to 5 cm on the floor | A softer finish in heavier, interlined fabrics |
Worked Example 1: A Tall Georgian Sash
These figures are illustrative, but the method is the one we use.
A sash window sits in a room with a 3.0 m ceiling. The pole is fixed high, and the finials are 2.4 m apart. The drop from the underside of the rings to the floor reads 2.71 m on the left, 2.69 m in the middle and 2.72 m on the right.
- Width: 2.4 m multiplied by 2.25 for a triple pinch pleat gives 5.4 m of finished curtain across the window, or 2.7 m for each of the two curtains.
- Length: the shortest reading is 2.69 m. Finishing 1.5 cm above the floor gives a finished length of 2.675 m, or 267.5 cm.
What the arithmetic does not show is weight. A curtain this long and this full is a lot of fabric hanging from one line, and without help it will swing and pull the heading out of shape. This is why tall windows call for hand sewn headings, weights in the hem and, often, an interlining. It is the approach we took for the tall Georgian window openings at The Washington Mayfair, and it is the single biggest difference between curtains that hang correctly and curtains that merely fit.
Worked Example 2: A Victorian Bay
Bays are where most measuring mistakes happen, because the hardware turns corners.
A three sided bay has a track that follows its faces, with the end sections each overhanging the bay by about 25 cm. Measured along the track, the total run is 3.2 m.
- Width: 3.2 m multiplied by 2.2 for a wave heading gives 7.04 m of finished curtain, or 3.52 m for each of two curtains meeting in the middle.
- Drop: measure from the glider at each face, not from one position, because a bay window sill and ceiling are often at slightly different heights from side to side.
- Check the stack back. Where a curtain draws into a corner of the bay, the fabric has nowhere to go. Make sure the track extends far enough past each end that the curtains can clear the glass.
Measure the track run, never the window opening. It is the same rule as for any window, but in a bay the difference between the two is large.
Windows That Are Not Standard
Not every opening is a rectangle. Arched tops, deep reveals, windows set above a radiator or a window seat, and openings that are neither a standard size nor a standard proportion (as in the Shoreditch courthouse) do not suit a formula. For these, a template taken on site is more reliable than a set of numbers, and a maker who can visit will usually get a better result than one working from a sketch.
The Mistakes That Cause Curtains to Hang Badly
- Measuring the window rather than the hardware.
- Measuring the drop once. Measure in three places.
- Skimping on fullness to save a little fabric.
- No allowance for the stack back, which makes the window look smaller than it is.
- Ignoring weight on tall curtains. Length without weight hangs badly.
- Forgetting the radiator. Decide deliberately whether a curtain finishes above it or covers it.
Lining and Interlining
A standard lining protects the face fabric from sunlight and gives body. A blackout lining blocks light. Interlining, an extra layer of soft fabric between the face and the lining, gives curtains a heavier, more luxurious fall and better insulation, which matters in older UK properties.
Ready Made or Made to Measure?
Ready made curtains come in standard sizes, commonly 168 cm or 228 cm wide and 137, 183 or 229 cm long. They suit a standard window. For a bay, a tall sash or anything irregular, made to measure is the only option that works, because the width, drop, heading, lining and weight are all set for the window in front of you.
We cut and make curtains to your specification, with the fabric chosen from the fabric library. Within West Yorkshire we can visit and measure for you. Our online shop, ZEBA Home, is coming soon, and will carry curtain and soft furnishing ranges from partners such as Designers Guild and Sanderson Design Group.
Planning Curtains for Your Home
If you would like curtains made for your home, see our residential interior design service, or book a consultation. You can also reach us at info@zebainteriors.co.uk or on 07982 778565. For how window treatments fit into a whole budget, see our guide to interior design costs in the UK.
