Curtain Calculator
Calculate curtain fabric: finished width from rod width and fullness, the number of panels to cut, and total yardage including hem and header allowances.
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What this tool does
Calculate curtain fabric: finished width from rod width and fullness, the number of panels to cut, and total yardage including hem and header allowances. Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
How to use the Curtain Calculator
- Enter or select rod / track width (inches).
- Enter or select finished drop / length (inches).
- Enter or select fullness (gather).
- Enter or select fabric width.
- Read the calculated result; change any measurement to compare alternatives.
Formula
Finished fabric width = rod width x fullness factor. Panels = ceil(finished width / usable fabric width). Cut length per panel = drop + 10 in (hem + header). Yardage = panels x cut length / 36.
- rod
- Rod / track width (inches)
- drop
- Finished drop / length (inches)
- fullness
- Fullness (gather)
- fwidth
- Fabric width
Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
Worked example
For curtain calculator, the following measurements illustrate the exact method: Rod / track width (inches): 60; Finished drop / length (inches): 84; Fullness (gather): 2; Fabric width: 54.
Inputs
- Rod / track width (inches)60
- Finished drop / length (inches)84
- Fullness (gather)2x — standard
- Fabric width54 in (standard decor)
Result
- Fabric to buy (yards)8
- Panels to cut3
- Finished fabric width (inches)120
- Cut length per panel (inches)94
- Exact yardage7.83
Results explained
- Fabric to buy (yards)
- Fabric to buy (yards) from the formula above. Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
- Panels to cut
- Panels to cut from the formula above. Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
- Finished fabric width (inches)
- Finished fabric width (inches) from the formula above. Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
- Cut length per panel (inches)
- Cut length per panel (inches) from the formula above. Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
- Exact yardage
- Exact yardage from the formula above. Usable width = fabric width - 2 in for side hems. The 10-inch length allowance covers a 4-inch base hem, header/tape and squaring — patterned fabric needing repeat matching needs extra per panel.
Frequently asked questions
Fullness is finished fabric width divided by rod width: 1.5x is a flat, tailored look, 2x is the standard recommendation for pencil and pinch pleats, and 2.5-3x suits sheer fabrics and formal goblet pleats.
At standard 2x fullness you need 120 inches of finished width — three panels of 54-inch fabric (52 usable) — and at an 84-inch drop, about 7.9 yards total. Enter your numbers to get the exact figure.
This calculator adds 10 inches per panel: roughly 4 inches for the bottom hem (folded twice), 4-5 for the header/tape casing, and a little to square the cut. Deep designer hems use more.
Common finishes: sill length, just below the sill, floor-skimming (1/2 inch clear), or puddling (2-6 inches extra). Measure the drop to where you want the hem to end and enter that as the drop.
Curtains stack back at the sides when open. Add 4-8 inches of rod width beyond each side of the window so the stackback does not block glass — the rod width you enter should be the full track length.