How is curtain fabric yardage calculated?

It multiplies the finished curtain width (adjusted for fullness ratio, typically 2-2.5x the window width) by the finished length plus hem and header allowances, then divides by fabric width to get total yardage.

What is "fullness ratio" in curtain making?

It's how much extra fabric width is used relative to the window width to create attractive gathers/folds when the curtain is closed — more fullness means a fuller, richer look.

Does pattern repeat affect fabric needed?

Yes — fabrics with a large repeating pattern often require extra yardage to match patterns across panel seams, which some calculators let you factor in separately.

Curtain & Drapery Fabric Calculator

Work out how much fabric to buy for curtains based on your window size and desired fullness.

Window / Track Width (inches)

Fullness Ratio (e.g. 2 = 2x width)

Curtain Drop / Length (inches)

Fabric Roll Width (inches)

Pattern Repeat (inches, 0 if plain)

Fabric Widths / Panels Needed -

Cut Length per Panel -

Total Fabric Needed -

What Is the Curtain & Drapery Fabric Calculator?

The Curtain & Drapery Fabric Calculator tells you how many widths of fabric to join and how much total fabric to buy to make curtains with the fullness (gathered look) you want.

Formula Used

Panels = ceil(Window Width × Fullness ÷ Fabric Width)
Total Fabric = Panels × (Drop + Hem Allowance)

A hem and heading allowance of 8 inches is added automatically. If you enter a pattern repeat, the cut length per panel is rounded up to the next full repeat so patterns line up between panels.

How to Use This Calculator

Enter your window or curtain track width in inches.
Enter the fullness ratio you want (2 is standard for a gathered look).
Enter your desired finished curtain drop (length) in inches.
Enter the width of the fabric roll you plan to buy.
Enter the pattern repeat if the fabric has one, then click Calculate.

Worked Example

For a 60-inch window with 2x fullness, you need 120 inches of fabric width. With a 54-inch-wide fabric roll, that's 3 panels. Each panel is cut at 84 + 8 = 92 inches, so total fabric needed is 3 × 92 = 276 inches, or about 7.7 yards.