Curtain Fabric Calculator
Built by Johnny Alto · free, no sign-up · updated July 26, 2026
Work out how much fabric to buy for a pair of curtains. Enter the rod width, the finished length you want, and how full the curtains should be, and the calculator figures the number of fabric widths to join and the total yardage, including an allowance for hems and the header.
Buy0yards total
Fabric widths0to seam together
Cut length0inches each
Covers the full window (both panels of a pair). Fullness is how many times the rod width of fabric you gather: 2x is the usual standard. The hem and header allowance defaults to 16 inches (roughly an 8-inch bottom hem and rod pocket or heading); adjust to your style. Add a full pattern repeat per width for prints.
How to measure fabric for curtains
Curtains take more fabric than their finished size because they are gathered for fullness and hemmed top and bottom. Start with the total width of fabric you need: multiply the rod width by a fullness factor, usually two, so the curtains look gathered rather than flat. Divide that by your fabric width and round up to find how many widths, or panels, you seam together.
Then set the cut length: your finished length plus an allowance for the bottom hem and the top header or rod pocket, commonly around 16 inches total. Multiply the number of widths by the cut length and divide by 36 for total yards. If the fabric has a pattern, add one full repeat to each width so the motifs line up across seams.
Fullness makes the look
Fullness is the single biggest choice. At 1.5 times the rod width the curtains look flat and casual, fine for sheers. Two times is the standard that reads as proper curtains, and 2.5 times gives a rich, luxurious drape that suits heavier fabrics and formal rooms. More fullness means more fabric, so it drives the yardage as much as the size of the window does.
Frequently asked questions
How much fabric do I need for curtains?
Multiply the rod width by your fullness (usually 2), divide by fabric width for the number of panels, then multiply panels by the finished length plus about 16 inches for hems, and divide by 36 for yards.
What fullness should curtains have?
Two times the rod width is the standard gathered look. Use 1.5x for flat, casual sheers and 2.5x for a full, luxurious drape.
How much extra for hems and the header?
About 16 inches total is typical, roughly an 8-inch bottom hem plus a rod pocket or heading. Adjust for your chosen hem depth and top style.
Do I add fabric for a pattern?
Yes. Add one full pattern repeat to each cut length so the design lines up across the seams between panels.
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This calculator gives estimates for planning only; always confirm against your own measurements and species research. Some links are to our buying guides, which contain affiliate links. As an Amazon Associate I earn from qualifying purchases.
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