How to Measure Curtains: The Exact Method Used by Professionals

Incorrect measurements are the single most common reason curtains look wrong after installation. Too short, too narrow, or hung at the wrong height — these mistakes are easy to make and expensive to fix. Follow this professional method to get it right the first time.

Step 1: Install Your Rod or Track First

Always measure after installing your rod or track, not before. The position of your rod determines your curtain drop, and the rod position should be decided based on your room's proportions, not the window size. As a rule, mount your rod 15–20 cm above the window frame and extend it 15–20 cm beyond each side of the frame.

Step 2: Measure the Drop

The drop is the distance from the top of your rod (or the bottom of your rings) to where you want the curtain to end. For floor-length curtains, measure to the floor and subtract 1–2 cm for clearance (so curtains don't drag). For a pooling effect, add 5–15 cm to your floor measurement.

Step 3: Measure the Width

Measure the total width of your rod or track from end to end. This is your track width, not your window width. For proper fullness, your curtain fabric width should be 2–2.5x your track width for standard fabrics, and 2.5–3x for lightweight sheers. This fullness is what creates the beautiful gathered look when curtains are drawn.

Step 4: Account for Heading Allowance

Different heading styles require different amounts of fabric at the top. Eyelet/grommet headings need 8–10 cm. Pinch pleat needs 15–20 cm. Tab top needs 20–25 cm. Add your heading allowance to your drop measurement to get the total fabric length required.

Common Measurement Mistakes

Avoid these errors that our consultants see regularly:

• Measuring the window frame instead of the rod/track
• Forgetting to add heading allowance to the drop
• Not accounting for fullness in the width calculation
• Measuring only once (always measure twice, cut once)
• Using a flexible tape measure that can sag — use a rigid metal tape for accuracy

When to Call a Professional

For standard rectangular windows, DIY measurement is achievable with care. For bay windows, arched windows, floor-to-ceiling glass walls, or any window over 3 metres wide, we strongly recommend a professional measurement visit. Our consultants measure for free as part of our home visit service.