Windows and decor
Curtain Panel Calculator
Estimate total curtain panel width, width per panel, rod width, and finished length from simple window measurements.
Curtain panel estimate results
- Rod width
- 72 in
- Total panel width
- 144 in
- Width per panel
- 72 in
- Finished length
- 84 in
- Metric per panel
- 182.88 cm
- Fullness
- standard gathered look
Saves in this browser only. Do not save sensitive personal or safety-critical project details.
Planning checklist
- Width per panel: 72 in
- Finished length: 84 in
- Check product width per panel or per pair.
Last reviewed: June 13, 2026
How this curtain calculator works
Curtain fullness is based on the planned rod width, not only the glass width. This tool adds side extension to both sides of the window, multiplies by fullness, then divides by panel count so you can compare product listings more clearly.
Curtain panel formula
Rod width = Window width + side extension x 2
Total panel width = Rod width x fullness ratio
Width per panel = Total panel width / panel count
Example calculation
A 60 in window with 6 in side extension on both sides has a planned rod width of 72 in. With 2x fullness and two panels, the curtains together need about 144 in of total width, or about 72 in per panel.
Common curtain measuring mistakes
- Buying based only on the glass width instead of the rod width.
- Confusing width per panel with width per pair.
- Choosing length before measuring the planned mount position.
- Ignoring header style, rod pocket size, or hardware limits.
Curtain calculator FAQ
How wide should curtain panels be?
Start with the planned rod width, multiply by fullness, then divide by the number of panels. Check whether the product lists width per panel or per pair.
What curtain fullness should I use?
A 1x ratio is flat, about 1.5x to 2x is a common gathered look, and higher ratios create a fuller decorative look.
Why does this calculator ask for finished length directly?
Finished length depends on rod height, sill or floor target, hardware, header style, and room layout. Entering the target length directly avoids guessing installation details.
Can this decide mounting hardware?
No. Hardware limits, mounting surface, child-safety requirements, and installation conditions should be checked with product instructions or qualified help.