Curtain size calculator.
Rod, fullness, panels, length, and the stock size nearest.
A curtain’s size is two numbers that come from different places. The width comes from the rod, the window plus the extension each side, multiplied by a fullness factor and split between the panels; the length comes from the rod’s height above the floor and the finish wanted at the hem. This page computes both, counts the stock panels that width takes and the fullness they really deliver, and names the stock length above and below the one measured.
02 / Elevation
03 / Size
- Rod width
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- Fabric across the rod
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- Stack each side
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- Length
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- Stock length above
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- Stock length below
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- Stock panels
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- Fullness delivered
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Stock panels are counted at the width chosen and evened for a pair; the fullness line is what those panels give on this rod.
Sizes by window width
| Window | Rod | Per panel | Panels at 50″ | Panels at 54″ | Per panel at 2.5× | At 3× |
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The per-panel column divides the fabric across the rod by the panels chosen; the stock-panel columns round the total up to whole 50- or 54-inch panels without evening for pairs. A 96-inch window at 2× takes exactly four 54-inch panels; a 100-inch window takes five and, for symmetry, six.
Fullness on this rod
| Fullness | Across the rod | Per panel | Stock panels | Delivered |
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Rod height for each stock length
| Stock length | Rod to floor needed | Against the rod entered |
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Three stock panels at 2.6× or four at 3.5×
The example window is 48 inches wide. With 6 inches of extension each side the rod is 60 inches, excluding finials, and at 2× the fabric across it is 120 inches: two panels of 60. A 52-inch stock panel is narrower than that, so the total needs three, which give 156 inches on a 60-inch rod, 2.6×. A pair cannot be three, and four panels give 208 inches, 3.5×, more than the deluxe 2.5× most publishers describe. The buyer can order four and accept the fullness, order three and hang two on one side, or move to 54-inch panels and 2× with two of them at 108 inches, which is a little under the rod times two. The ledger prints all of it; the tool executed for this page prints “3 at 52 in” and stops.
Length is the rod’s height. At 84 inches from the floor with a kiss finish the stock 84-inch panel lands exactly; hover half an inch above and it is 83.5, the 84 shortened by half an inch. Raise the rod to 90 inches for a taller window and no stock length fits: 96 shortened by 6, or 84 and 6 inches short. Publishers disagree on the finish, and the options carry their names: hover at half an inch, a one-inch break, and a puddle of 3 or 6 inches from Home Depot’s guide.
Where the extension comes from
The extension is the part of the rod past the frame, where the open panels stack. The AI Overview says 4 to 12 inches, Home Project Calculator defaults to 4, TwoPages recommends 6 to 15, Jane Clayton 6 to 14 and House of Ekam 10 to 12. Six is preloaded as an example inside every range; the chart recomputes with whatever is entered. Rod height above the frame is the other disputed number, 4 to 6 inches for most publishers and 6 to 10 for one, and it is folded into the rod-to-floor measurement rather than asked separately.
Conventions by publisher
| Publisher | Fullness |
|---|---|
| Home Depot | curtain widths at least two to three times the length of the rod |
| Omni Calculator | standard ×2, deluxe ×2.5, ultra ×3 of the window width |
| Sailrite Fabric Calculator | options 1.25, 1.5, 2, 2.5, 3; 1.5 for thicker fabrics, 2 average for draperies, 3 for sheers |
| Home Project Calculator | 1.5–2 grommet and rod pocket, 2–2.5 pleated, 2+ sheer; defaults 2.0 standard and 2.2 pleated |
| sew-helpful | pencil pleat 2.5, double pleat 1.6–2.4, triple pleat 2.5, goblet 2.5, cartridge 2.2–2.4, inverted pleat 1.6–1.8 |
| Publisher | Extension each side |
|---|---|
| AI Overview (Google) | 4 to 12 in |
| Home Project Calculator | 3 to 6 in, default 4 |
| TwoPages | 6 to 15 in |
| Jane Clayton | 6 to 14 in |
| House of Ekam | 10 to 12 in |
| Publisher | Floor finish |
|---|---|
| Home Depot | hover 0 in · trouser break +1 in · puddle restrained +3 in · puddle lavish +6 in |
| Home Project Calculator | hover -0.5 in · kiss 0 in · slight break +1 in · puddle +6 in |
| AI Overview (Google) | clean -0.5 in · puddle 1 to 2 |
| TwoPages | float -1 in · kiss 0 in · puddle +1 in |
| House of Ekam | above the ground -1 to -2 · puddle 1 to 2 |
Stock lengths: Home Depot and Home Project Calculator list 63, 84, 96, 108 and 120 inches; Omni lists 72, 84, 96 and 108. Stock panel widths: 50 to 54 inches from the AI Overview and Home Project Calculator, 42 to 43 from House of Ekam’s own panels. The yardage to sew these panels, with widths, hems and repeats, is worked on the curtain fabric calculator.
Questions before the panels are ordered
How do I calculate curtain sizes?
Width first: the rod is the window width plus an extension each side, and the fabric across the rod is that width times a fullness factor, 2 for a standard gather, 2.5 or 3 for a fuller one. Divide by the panels for the width each must be. Length: measure from the rod, or the bottom of the rings, to the floor and add or subtract the finish, half an inch above, a one-inch break or a puddle. The calculator prints both and the stock sizes nearest to them.
How wide should curtains be for a 96-inch window?
With 6 inches of extension each side the rod is 108 inches. At 2× the panels total 216 inches, 108 each for a pair; four 54-inch stock panels cover it exactly at 2×, six 50-inch panels give 2.8×. At 2.5× each panel is 135 inches and the pair needs five 54-inch panels, six for symmetry. The chart below runs the same figures for eleven widths.
What size curtain for a 100-inch window?
Rod 112 inches with the 6-inch extensions. At 2× that is 224 inches of fabric, 112 per panel of a pair, five 54-inch stock panels rounded to six for symmetry, which then hang at 2.9×. At 2.5× the pair needs 280 inches, six 54-inch panels exactly. Enter 100 in the width field and the ledger, chart and drawing update.
How long should curtains be for a 72-inch window?
The window width does not set the length; the rod height does. Measure from where the rod sits to the floor, add the finish you want, and read the stock length nearest. A rod 84 inches above the floor with a kiss finish takes 84-inch panels; hung 4 inches higher it needs 88 and the 96-inch stock length shortened by 8. The length table lists the rod height each stock length wants.
Is there a curtain size chart?
Yes, computed rather than printed: eleven window widths from 36 to 144 inches with the rod width at your extension, the width per panel at your fullness and at 2.5× and 3×, and the count of 50- and 54-inch stock panels each takes. It changes with the fields above and exports as CSV.
Does it work in metres?
Switch the toggle to metric and every field converts: window, extension and rod height in millimetres, the chart in centimetres. The stock lengths stay the American 63, 84, 96, 108 and 120 inches, shown in centimetres, because those are the sizes on the shelf; European stock drops of 137, 183 and 229 centimetres are a different range and are not modelled.
What are standard curtain sizes in cm?
The American stock lengths are 160, 213, 244, 274 and 305 centimetres, that is 63, 84, 96, 108 and 120 inches, and stock panels are 127 to 137 centimetres wide, 50 to 54 inches. Two publishers list 63 to 120; one lists 72 as well. The page rounds to the American set and says how much to shorten.
Can I see sizes in both cm and inches?
The ledger shows the system selected; switch the toggle and the same figures appear in the other. The chart and the stock lengths convert with it, so 84 inches reads 213.4 centimetres and a 48-inch window 121.9.
Why not calculate curtain size in square feet?
A window of 48 by 60 inches is 20 square feet, and that number says nothing about the panel: the width comes from the rod and the fullness, the length from the rod height, and neither multiplies into an area. Square feet matter for fabric buying only after the cut widths and cut drops exist, which is the fabric page’s job.
Is this a window curtain calculator or a door one?
Any opening with a rod above it. A sliding door 72 inches wide and 80 high with the rod 6 inches above takes the same arithmetic: rod 84 with 6-inch extensions, 168 inches of fabric at 2×, and a rod height of 86 from the floor, so the 96-inch stock length shortened by 10 with a kiss finish.
Does it take inches and fractions?
Yes: 48, 48 in, 4 ft, 4′ 0″ and 48 1/2 are all read, and results print to the eighth of an inch. Stock panel counts are whole numbers; the fullness they deliver is printed to one decimal.
Is there an app?
No app. The page runs in the browser, prints the ledger, chart and drawing to PDF, exports the chart as CSV and the elevation as SVG. Nothing is stored or sent.
What the size does not decide
- Rectangular windows with a straight rod; bay windows, arches and tracks that return to the wall are not modelled.
- Rod-to-floor is measured by the reader; heading styles that hang below the rod, rings or clips, shorten the panel and are the reader’s adjustment.
- Stock panels are counted by width only; their stock length is read from the length lines.
- Extension, fullness, finish and panel width are example values quoted from publishers who disagree; none is a standard.
- No hardware sizing beyond the rod width, no prices.