Loading TrackFit...
Free planning tool
Curtain Stack-Back Calculator
Estimate how much space your curtains may occupy when fully open and how much of the track may remain clear.
Step 1
Enter the track length
Use the full length of the curtain track, including any extension beyond the window.
Step 2
Choose the curtain heading
Step 3
Choose the fabric bulk
Think about how thick the curtains feel when gathered together, not only the face fabric.
Step 4
How will the curtains open?
What the result means
The estimate is intended for early planning. It helps show whether the curtains are likely to stack neatly beside the opening or continue covering part of the glass when open.
Questions answered
Frequently asked questions
What is curtain stack-back?+
Stack-back is the space occupied by the curtains when they are fully open. It affects how much glass remains covered and how far the track should extend beyond the window.
Is curtain stack-back an exact measurement?+
No. It varies with the fabric, lining, fullness, heading construction and how the curtains are dressed. The calculator provides a practical planning estimate.
Do wave curtains need more stack space?+
Wave curtains maintain regular folds when open, so they normally need a predictable and often slightly larger stack allowance than a simple pencil-pleat curtain.
Should the track extend beyond the window by the stack-back amount?+
Where wall space allows, providing enough extension for the curtain stack helps uncover more glass. The available wall, handles, radiators and furniture must also be considered.