Curtain fabric calculator.
Widths across, drops down, the repeat between.
Drapery fabric is bought by the yard at a fixed width, and a panel is sewn from whole widths of it cut to a drop that carries the header, the hem and the pattern repeat. The yardage tools read for this page print a number; this one prints the cut list the number comes from, draws the drops on the bolt, and sets the lining and two published rules beside it.
02 / On the bolt
03 / Yardage
- Exact
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- Widths
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- Cut width
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- Cut drop
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- On the repeat
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- Drops to cut
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- Matching waste
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- Lining
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- Trimmed per panel
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- One-width rule
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- Cost
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The one-width rule is Best Fabric Store’s published shortcut, printed for comparison; the yards above come from the cut list.
The cut list
| Panel | Finished width | Cut width | Widths | Cut drop | Fabric |
|---|
Three bolt widths
| Fabric | Widths per panel | Seams | Trimmed | Yards | To order |
|---|
What a repeat costs
| Repeat | Adjusted drop | Lost per drop | Yards | To order |
|---|
Eleven yards, not six
The example pair hangs on a 60-inch rod at 2.5×: 150 inches of fabric across, 75 finished per panel. Add 2 inches of side turning each side and the panel needs 79 inches of fabric, more than one 54-inch width, so it takes two, seamed, and the half-inch seam allowances make the cut width 80. Two widths per panel, two panels, four drops. Each drop is the 84-inch finished length plus a 4-inch header, an 8-inch double hem and 2 inches of trimming: 98 inches. Four drops of 98 are 392 inches, 10.9 yards, 11 to order, and each panel trims a 28-inch strip from its second width.
The shortcut one retailer publishes, 16 inches per panel and one width each, gives 200 inches for the same pair, 5.6 yards, 6 to order. It is not wrong for a 40-inch panel in 54-inch fabric; it is five yards short for a 75-inch one. The ledger prints it beside the cut list so the buyer sees which panel width the shortcut assumed. Sailrite’s tool, executed with a 48-inch window at 2×, printed 6.22 yards and “1.61 fabric widths per curtain”, a fraction a scissors cannot cut; this page rounds to whole widths, or half widths when the box is ticked, and says what is trimmed.
The repeat, and the lining
Give the fabric a 24-inch repeat and the 98-inch drop rounds to 120, five repeats, because every drop must start at the same point of the pattern to match at the seams. Four drops lose 88 inches, and the order becomes 14 yards. A 27-inch repeat rounds to 108 and costs 40; the repeat table shows six so the fabric can be chosen with the waste in view. Lining follows the drops without the repeat: 84 plus 2 for the header, a 6-inch double hem and 2 of trimming, 94 inches, four drops, 376 inches, 11 yards.
A published chart, for comparison
| Finished length | Solids, small prints | Medium prints, repeat to 12 in | Large prints, repeat to 24 in |
|---|---|---|---|
| 60 in | 4.5 yd | 5 yd | 5.5 yd |
| 70 in | 5 yd | 5.5 yd | 6 yd |
| 80 in | 5.5 yd | 6 yd | 6.5 yd |
| 90 in | 6 yd | 6.5 yd | 7 yd |
| 100 in | 6.75 yd | 7 yd | 7.25 yd |
| 110 in | 7.25 yd | 7.5 yd | 7.75 yd |
| 120 in | 7.75 yd | 8 yd | 8.5 yd |
The chart assumes one width per panel and its 16-inch allowance; at 80 inches it says 5.5 yards where the cut list above, on two widths, says 11. The panels the chart fits are 54 inches or narrower, a 40-inch rod at 2.5× or a 54-inch rod at 2×. Sizes that need wider panels come from the curtain size calculator, which counts stock panels and fullness before any fabric is cut.
Questions before the bolt is cut
How do you calculate how much fabric you need for curtains?
Two counts. Across: the finished width of each panel plus the side turnings, divided by the fabric width and rounded up to whole widths, is the number of drops each panel takes. Down: the finished length plus the header allowance, the hem allowance and a trimming allowance is the cut drop, rounded up to whole pattern repeats when the fabric has one. Drops times the cut drop is the fabric, in inches; divide by 36 for yards.
How do I calculate the yardage for drapery fabric with a repeat?
Round each cut drop up to a whole number of repeats. A 98-inch cut drop on a 24-inch repeat becomes 120, five repeats, and four drops cost 88 inches of matching waste, nearly two and a half yards. The repeat table runs six repeats on your panels so the waste of each is visible before the fabric is chosen.
How much material do I need for my curtains?
For the example pair on a 60-inch rod at 2.5×, 84 inches long, in 54-inch fabric with a 4-inch header, an 8-inch double hem and 2 inches of trimming: two widths per panel, four drops of 98 inches, 392 inches, 10.9 yards, 11 to order, and 11 of lining. Change any field and the ledger, the bolt drawing and the cut list follow.
How many yards for 84-inch curtains?
It depends on the widths, not only the length. With one width per panel and the 16-inch workroom allowance one retailer publishes, two 84-inch panels are 200 inches, 5.6 yards, 6 to order. With two widths per panel, which a 75-inch finished panel in 54-inch fabric needs, the same length is 11 yards. The ledger prints that one-width rule beside the cut list so the difference is not a surprise at the counter.
How do I calculate curtain fabric in metres?
Switch the toggle to metric: every allowance converts to millimetres and the result reads in metres of fabric. The arithmetic is the same, widths across and drops down; the fabric width becomes 137 centimetres for a 54-inch bolt.
Does it take inches and fractions?
Yes. Fields read 84, 84 in, 7 ft, 7′ 0″ and 84 1/2; cut widths and drops print to the eighth of an inch and yards to two decimals with the whole-yard figure to order. Half widths can be allowed for panels that need a width and a half.
What about sheer curtain fabric?
Sheers hang at 3× in the tools read, so the panels are wider and take more widths; sheer fabric often comes 118 inches wide and is used sideways, which this page does not model. Enter the width on the bolt and the fullness the size page gave; for sideways use the length becomes the width, and that plan is out of scope here.
Why not buy by square feet?
Fabric is sold by the linear yard at a fixed width, and the drops must be whole cuts of that width. Two panels needing 80 inches of a 54-inch bolt use two widths each and trim 28 inches from every one; the square feet bought are the drops times the bolt width, which the ledger prints as the spare strip.
Is this a window curtain fabric calculator only?
Any flat curtain: window, door, shower or room divider. The panel width can be entered directly instead of from a rod and fullness, so a stated finished size is planned as it is.
Does it match a retailer’s calculator?
Two published rules are printed for comparison: the sew-helpful rounding of each drop to whole repeats, which this page uses, and the Best Fabric Store rule of 16 inches per panel with one width each and the repeat added to every panel after the first. Retailer tools that sew the curtains for you, John Lewis among them, work to their own allowances, which are not reproduced here.
Is it free?
Yes, and it prints without a code: the cut list, the bolt drawing and the tables go to PDF, and the cut list exports as CSV. Nothing is stored or sent.
Is there an app?
No app; the page runs in the browser on a phone at the fabric counter. The header, side turning, seam and price fields are example values marked as such; the hem, trimming and lining allowances are quoted from a curtain-making workroom.
What the yardage does not decide
- Flat panels from whole or half widths; no railroaded fabric, no half-drop repeat, no interlining.
- Allowances marked as exercise values are working figures, not workroom instructions; hems, trimming and lining hems are quoted from sew-helpful, the 12 and 16 inch totals from Jane Clayton and Best Fabric Store.
- Widths are cut from one bolt in sequence; offcuts are not reused across panels.
- Yards to order are whole yards; stores may cut to the eighth or the quarter.
- Price is the reader’s figure; no tax, shipping or heading tape.