How to use
- Measure the usable face width of the installed rod or track, excluding decorative finials.
- Enter the desired finished length and a fullness multiplier specified for the heading or look you intend to use.
- Choose a whole panel count. Add any total width allowance for returns or overlap and the full length allowance for header plus hem.
- Calculate the flat width and cut length of each equal panel. Confirm the numbers with the heading system before cutting.
Formula and interpretation
Total flat width = rod width × fullness + total width allowance. Divide by the number of panels for equal flat panel width.
Finished coverage per panel is rod width ÷ panels. Cut length per panel = finished length + the entered length allowance.
Worked examples
Two-panel pair
A 200 cm rod at 2× fullness, two panels and 20 cm total extra width gives 420 cm total flat width, or 210 cm per panel.
Cut length
With a 220 cm finished length and 25 cm combined header-and-hem allowance, each panel cut length is 245 cm.
Limits and practical checks
- Fullness requirements vary by heading tape, pleat style and fabric; follow the selected hardware instructions.
- The calculator does not infer side hems, returns or center overlap: include the total desired value yourself.
- Fabric bolt width, pattern repeat, joining and yardage are outside this page.
Frequently asked questions
Is fullness applied to each panel?
Fullness is applied once to the whole rod width, then the total is divided equally by panel count.
What belongs in width allowance?
Use one combined total for any returns, center overlap or other width you intentionally add beyond fullness.
What belongs in length allowance?
Enter the combined extra length needed for the selected header and bottom hem on each panel.
Does this select a curtain size to buy?
No. Compare the calculated flat width and finished length with the actual product specifications.