Specific calculators, planners, and explainers for jobs that usually get buried in forums.
HTML-first, no account wall
Shareable URLs and direct outputs
Curtains and blinds · Planner
Curtain fullness and stack-back planner
Work out how wide your curtains should be, how many fabric widths each panel needs, and how much glass they will still uncover when open. The planner combines heading style, desired look, fabric width, and stack-back behaviour instead of stopping at a single multiplier.
How to use the result
- If you only know the glass width, leave measurement mode on window width and use side returns to plan a wider rod or track.
- If you already own the track or pole, switch to track width so the planner sizes panels around the real span.
- Fullness is not universal. Pencil pleat and pinch pleat usually want more width than eyelets or wave headings.
- Stack back matters if you care about daylight. A curtain can size correctly when closed but still cover more glass than expected when open.
- Pattern repeat is optional. Add it when matching a printed fabric because it can change how much yardage you need to buy.
Recommendation
Fabric plan
Open-window impact
When to increase fullness
- Sheers often look better when they are fuller because the fabric is light and visually sparse.
- Tall windows and formal rooms usually suit more generous heading depth and smoother folds.
- If you dislike a stretched-flat look when the curtains are closed, move up a fullness tier before buying.
When stack back matters most
- Small bedroom windows can lose a surprising amount of daylight if the returns are tight and the headings are bulky.
- Blackout curtains need more overlap to seal well, so they often uncover less glass when open than a sheer pair.
- One-way draws can be practical, but they need more wall space on the stacking side.
Common questions
How wide should curtains usually be compared with the window?
The answer is usually based on track width and fullness, not glass width alone. Many setups land around roughly two times fullness, but heading style and desired look change that.
What is stack back?
Stack back is the width curtains occupy when fully open. It matters because a design can look full when closed but still block too much glass when parked open.
Why does fabric width matter?
Fabric width changes how many widths you need per panel and therefore changes total yardage or metreage. A good curtain plan is partly a buying calculation, not just a styling decision.