Curtain Panel Calculator
Measure your window, pick a fullness factor, and include hem allowances to plan custom drapery or confirm ready-made panel coverage.
Panels needed
4
Total coverage 144.0 inches
Finished panel size
Width 36.0 inches
Length 94.0 inches
Usable width per panel 47.0 inches
Fabric yardage
Per panel 2.61 yards
Total 10.44 yards
How to Use This Calculator
Measure the window area
Measure the width and height you plan to cover, including any desired overlap for privacy or stack back.
Select fullness
Use 1.5 for tailored pleats, 2 for standard gathers, and 2.5 to 3 for very full or sheer panels.
Enter hem allowances
Add seam allowances for side hems, rod pocket, header, and the bottom hem to reach the final cut length.
Review panel count and yardage
Use the results to decide how many panels to sew or purchase and how many yards of fabric to buy.
Formula
Panels = ceil(Window width x Fullness / (Panel width - 2 x Side hem))
Panel length = Window height + Top hem + Bottom hem
Fabric yards per panel = Panel length / 36
Total fabric yards = Fabric yards per panel x Panels.
Example: 72 inch window, fullness 2, panel width 50, side hem 1.5 results in usable width 47 inches and four panels (two on each side).
Full Description
Planning curtain panels requires balancing fullness, hems, and fabric width. This calculator does the math so you can order or cut fabric with confidence and avoid curtains that fall short of the window.
Adjust the fullness factor to match the look you want, and tweak hem allowances if you plan pinch pleats, grommets, or tab tops. The results display both panel count and yardage so you can compare custom sewing to ready-made options.
Bring the numbers with you when shopping for fabric or working with clients to present realistic yardage estimates and design recommendations.
Frequently Asked Questions
What fullness factor should I choose?
Use 1.5 for minimal gathers, 2 for standard pleats, and 2.5 to 3 for luxurious or sheer drapery.
How do I split panels between sides?
Evenly divide the total panel count. For example, four panels means two on each side of the window.
Does this account for lining?
Use the same calculations for lining fabric. Many sewists cut lining to match the face fabric length and reduce the width slightly for a clean finish.
What if my fabric has a pattern repeat?
Add extra length equal to at least one pattern repeat per panel to align motifs across seams.
Can I round the yardage?
Always round up to the next quarter yard to ensure enough fabric, especially when matching patterns or pre-washing.