To measure for curtains, establish the finished pole or track width, decide where the fabric should end, then measure the drop from the point specified for your curtain heading. Before ordering, check whether the listed width describes one panel, a pair or the window coverage of a finished curtain.
Those distinctions matter more than choosing the nearest attractive size on a product page. A window measurement helps you plan the hardware, but it does not automatically tell you how much fabric to buy. Work through one window completely before copying the process to another.
Make a Measurement Record
Use a steel tape measure, paper and a pencil. A second person can help keep a long tape straight. If a point is beyond comfortable reach, use appropriate access equipment safely or ask someone qualified to measure it; do not balance on furniture.
Sketch the window and label the room. Record centimetres or inches consistently, with the unit beside every number. A note saying only “180 by 220” leaves too much room for confusion later.
Keep separate lines for:
- The window opening and available wall space.
- The usable pole or track width.
- The heading style and drop measurement starting point.
- The intended bottom edge of the curtain.
- The seller’s panel quantity and sizing instructions.
Add a photograph of the hardware if you are asking a shop for help. A clear picture can explain a ring, bracket or track arrangement more reliably than an uncertain description.
Measure in This Order
Confirm the hardware position.
If a pole or track is already fitted and will stay, use that installation as your reference. If you are replacing it, settle its position before ordering a final curtain length. Moving a pole upwards later changes the required drop.
For new hardware, first measure the window and inspect the wall on both sides. Allow room for the curtains to gather when open, while checking nearby corners, cupboards and doors. The extension needed depends on the fabric, heading and available space; a universal allowance will not suit every room. Check the hardware supplier’s planning and fitting instructions.
Measure the usable pole or track width.
For an ordinary straight pole, measure between the decorative end pieces, excluding those pieces themselves. For a simple track, measure its working length. Do not substitute the width of the glass or the outside of the window frame.
Note any overlap arm, return or unusual bend. These details can affect a made-to-measure order. Bay windows and specialist tracks deserve the supplier’s dedicated measuring method rather than a straight-window shortcut.
Identify the curtain heading.
The heading is the top section that attaches the curtain to its support. Eyelets slide directly onto a suitable pole; pencil-pleat curtains usually hang from hooks attached to rings or track gliders. Their measuring reference points differ.
For eyelets, suppliers commonly use the top of the pole as a reference, with fabric extending above it. For hooked curtains, the relevant point is usually the ring eye or the specified track/hook position. Read the exact product instructions before recording a final drop: do not add an assumed heading allowance twice.
Choose the bottom edge and measure the drop.
Decide whether you want the fabric to finish near the sill, below it or close to the floor. Consider furniture, window handles, door movement and cleaning access. Check heating-appliance clearance instructions wherever relevant.
Measure vertically from the correct heading reference to the intended endpoint. Repeat at the left, centre and right, especially for floor-length curtains. Write down all three readings; an uneven floor is easier to discuss with a maker when you have the actual figures. Tell the supplier the finish you want instead of silently choosing one measurement and hoping it works.
Translate coverage into fabric width.
Curtains need extra fabric to form folds when closed. This is called fullness. The appropriate amount depends on the heading, material and desired appearance, so use the chosen product’s guidance.
For illustration, suppose a straight pole has a usable width of 180 cm and a ready-made curtain’s instructions call for total flat fabric width equal to twice the pole width. The calculation is 180 × 2 = 360 cm across the curtains together. Two panels each 180 cm wide would supply that amount. This is an example, not a rule for every curtain.
Made-to-measure services may ask for the pole width and calculate fullness themselves. Entering 360 cm when the form asks for a 180 cm pole would confuse fabric width with coverage. Follow the field labels rather than applying your own multiplier automatically.
Check the order against the record.
Read the size label and quantity together. “Width 180 cm” is incomplete information until you know whether it means each panel, the whole pair or the coverage of a finished pleated curtain. Confirm the heading is compatible with your pole or track too.
If your required drop sits between ready-made lengths, investigate an appropriate longer option and alteration before buying. Check the fabric care instructions and return terms first, especially before hemming or ordering custom work.
Keep Similar Numbers Separate
A small comparison table can prevent the most common mix-ups:
| Measurement | What it tells you |
|---|---|
| Window opening width | The opening you need to cover and a starting point for planning hardware. |
| Pole or track width | The curtain coverage reference requested by many suppliers. |
| Total flat fabric width | The material available across the panels before gathering. |
| Finished drop | The required hanging length, using the specified heading reference. |
Do not transfer measurements from an old curtain without checking how it was hung. Its previous heading, alterations or fit may differ from the replacement you want. Use it as a comparison after measuring the current installation.
Do a Final Room Check
Before paying, imagine opening the window, drawing the curtains and walking past them. Check that the planned arrangement works with furniture and everyday movement. A floor-pooling style may look appealing in a photograph but require a different cleaning routine from a curtain that clears the floor.
Avoid assuming that longer fabric solves other window problems. If moisture collects around the glass, assess ventilation and the conditions behind the curtain; our guide to managing indoor humidity explains that separate issue. For washable fabric, follow its own label rather than a general rule; the clothing care guide introduces the habit of checking care instructions before washing.
Keep your sketch with the order confirmation. The useful result is a record that connects the installed hardware, heading, finished length and purchased quantity. When those agree, choosing a colour or pattern becomes a much simpler decision.
