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Curtain Rod Length Calculator
Calculate working rod length and total finial span from the window and stack-back. Results update as you type and all assumptions stay visible.
ROD SPAN
Working length and finial span
The calculator uses the larger of extension and stack-back. It does not determine rod strength, brackets, fixings, or load capacity.
WORKING ROD LENGTH
72 inMETHOD
How the calculation works
Working rod length equals window width plus usable side space on both sides. The calculator uses the larger of the entered extension and estimated stack-back so the planning result does not ignore the open curtain.
Finials are added only to the overall decorative span. They are not counted as working travel length for the panels.
Rod strength, brackets, fixings, wall substrate, and load capacity remain product-specific and outside this sizing calculation.
Estimate, then verify
Measure the actual window and selected product. Manufacturer dimensions, heading systems, fabric behavior, and pattern matching can change the result. These tools do not determine hardware strength, fixings, or a guaranteed fit.
SOURCE NOTES
What this page is based on
Measurements here combine mathematical results with labeled commercial conventions and design recommendations. Disagreements are kept as ranges rather than averaged into a false standard.
- BETYDLIG/RÄCKA/HUGAD buying guide — Measure your windowIKEA · reviewed 2026-09-11
Primary manufacturer guide: add at least 6 in each side, add 6 in above, and use 2–2.5× rod width for panel planning.
- VIDGA — How to measure your windowsIKEA · reviewed 2026-09-11
Current manufacturer track-system guide with measured-window diagrams, minimum side extension, stack-back planning, and hanging-point length references.
- Buying curtainsJohn Lewis & Partners · reviewed 2026-09-11
Retailer/workroom guidance on pole extension, hanging references, sill/floor endpoints, ready-made metric ranges, and double fullness.