Curtain Size and Fabric Calculator

Size panels or plan fabric

Enter the rod width you want covered, your chosen fullness and panel count. The finished width result helps compare ready-made panels. For sewing, also enter the finished drop, fabric width, hem and seam allowances, and any vertical pattern repeat. Results update automatically and can be copied or downloaded.

Fullness is extra flat width

Combined flat curtain width equals rod coverage multiplied by fullness. Divide that width by the number of panels to obtain each panel’s finished flat width. For example, a fullness of two provides twice as much flat fabric as the rod coverage. The appropriate fullness depends on the fabric and heading style; choose it from your sewing pattern or supplier guidance rather than treating the starting value as universal.

Worked example: two panels

A sixty-inch rod at two-times fullness needs 120 inches of combined flat width. With two panels, each finished panel is sixty inches wide. Using 54-inch fabric, four inches of total side-hem allowance per panel and half-inch allowances at each joined edge, each panel needs two full fabric widths. Four widths are therefore cut for the pair.

For an 84-inch finished drop with twelve inches of combined top and bottom allowance, each cut is 96 inches long. With plain fabric, four cuts require 384 inches, or 10.6667 yards. A twenty-inch vertical repeat rounds each cut up to 100 inches, so the total becomes 400 inches, or 11.1111 yards, before any additional purchase allowance.

Joining fabric widths

The usable width of a panel made from N widths is N times the fabric width, minus two seam allowances for every join, minus the panel’s total side-hem allowance. The calculator chooses the smallest whole N that reaches the requested finished width. It allocates full widths separately to each panel; it does not optimize narrow strips or share leftover pieces between panels.

Assumptions and sewing limits

The yardage estimate assumes vertically hung fabric and straight pattern matching. Half-drop repeats, railroaded fabric, shaped windows, interlining, lining and specialty headings require a separate cutting plan. Pattern placement at the top of the first panel may require extra fabric beyond repeat rounding. Add shrinkage and practical cutting allowances according to your fabric and preparation method.

Measure from the installed rod or the intended mounting position. Window glass width alone may exclude the extra rod coverage needed beside the opening. Drop should already account for your desired clearance or floor treatment. Choose inches, feet, centimeters or meters for your measurements. Switching units converts all entered lengths without changing the project, including small seam allowances. Fullness and panel count stay unchanged. Panel and cut dimensions use your selected unit; total fabric length is always shown in both meters and yards.

Curtain sizing FAQ

Are panel widths gathered or flat?

The result is finished flat width before gathering. Check how a retailer describes its panels before comparing sizes.

Does yardage include lining?

No. Lining has its own width and allowance requirements. Calculate it separately from the face fabric.