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Free measurement tool
Curtain Track Length Calculator
Enter your opening width and choose how far the track should extend at each side. Your result updates instantly.
Step 1
What are you measuring?
Choose the opening that most closely matches your installation.
Step 2
Enter the opening width
Measure the full window or door opening, not only the visible glass.
Step 3
Choose the curtain style
This helps tailor the installation guidance shown with your result.
Step 4
Choose the side extension
This is how far the track extends beyond the opening on each side.
Compare options
See how the extension changes the result
Standard
20 cm each side
280 cm
More stack-back
30 cm each side
300 cm
Maximum coverage
40 cm each side
320 cm
How the calculation works
Recommended track length equals the opening width plus the selected extension at the left and right. It is a planning estimate, not a substitute for checking the fixing surface, curtain weight or manufacturer guidance.
track length = opening width + left extension + right extension
Questions answered
Frequently asked questions
How much wider should a curtain track be than the window?+
For a straightforward window, around 20–30 cm beyond each side is a useful starting point. More may be needed for thick curtains, wide doors or greater stack-back.
Should I measure the glass or the full opening?+
Measure the full window or door opening. The calculator then adds the selected extension at each side.
Can I use this calculator for a bay window?+
It can provide a basic straight-width estimate, but a bay needs every section and angle measured separately.
Can the track be longer than the result?+
Yes, where wall space allows. A longer track may improve stack-back and light control if it is properly supported.
Professional installation
Your measurement is ready. Now make sure the installation is right.
Send us the result and a few photos. We’ll check the fixing surface, mounting position, track type and curtain clearance before providing a quote.
✓
Check the recommended track length
✓
Assess ceiling or wall mounting
✓
Review the fixing surface
✓
Check clearance around handles and radiators
Send us
- 01Your postcode
- 02Your measurements
- 03Photos of the window and fixing area
- 04Details of any track already purchased