Curtain Fabric Calculator

Frequently asked questions

How much fabric do I need for curtains?

Multiply your curtain rod width by the fullness ratio of your heading style (e.g. 2.5x for pinch pleat), divide by your fabric width minus side hems, and round up to get the number of fabric widths. Then add hem allowances to your finished drop length (rounding up to the pattern repeat if the fabric is patterned), and multiply widths by cut length. The calculator above does all four steps instantly.

What is curtain fullness, and how much do I need?

Fullness is the ratio of flat fabric width to finished curtain width — it creates the folds. As a rule of thumb: pinch pleat and pencil pleat 2.0–2.5x, grommet/eyelet 1.5–2.0x, rod pocket 1.5–2.0x, tab top 1.25–1.5x, wave/ripplefold 1.8–2.4x, sheers 2.5–3.0x, flat panels 1.0–1.25x. This calculator sets the recommended fullness automatically for each heading style, and you can fine-tune it with the slider.

How do I calculate fabric for pinch pleat curtains?

Pinch pleats need 2.0 to 2.5 times fullness — 2.5x is the standard for a full formal look. Multiply rod width by 2.5, divide by usable fabric width (fabric width minus side hems), and round up to whole widths. Choose “Pinch pleat” in the calculator and it applies 2.5x automatically with hem allowances included.

How do I match patterns when calculating curtain fabric?

For patterned fabric, every cut panel must start at the same point in the pattern, so each panel’s cut length is rounded up to a whole number of pattern repeats. Enter the vertical pattern repeat (found on the fabric bolt or listing) and the calculator rounds each panel up — e.g. a 260 cm cut with a 64 cm repeat becomes 320 cm. This is the step most basic calculators skip, and it is where DIY makers most often run short.

Should I measure curtains in inches or centimeters?

Either — use whichever you are comfortable with. Switch between Metric and Imperial above; the calculator converts everything internally and shows results in both yards and meters. US fabric is usually sold by the yard in 54-inch widths; UK/EU fabric is usually sold by the metre in 137 cm widths.

Should I make one curtain panel or two?

Two panels (a pair) is standard for most windows: they stack on both sides and close in the middle. One wide panel suits narrow windows or a one-sided stack look. If you are wondering how many panels of curtains you need, the rule is simple: pairs for windows wider than about 36 inches (90 cm), a single panel for narrower ones. The calculator splits the total fabric widths across your chosen panel count and shows the flat width of each panel.

How much fabric do I need for 84-inch curtains?

For an 84-inch (213 cm) finished drop with pinch pleats (2.5x fullness) on a 60-inch rod using standard 54-inch fabric: you need 3 fabric widths, each cut to about 92 inches, for a total of roughly 7 3/4 yards (about 7.1 m). So if you are asking how many yards of fabric for 84 inch curtains, the answer for this common setup is about seven and three-quarter yards. Enter your exact rod width above — wider rods or patterned fabric will increase it.

Do blackout or lined curtains need more fabric?

The face fabric yardage is the same — blackout coating or lining does not change the fullness math. If you are adding a separate lining, calculate it the same way (usually with slightly less fullness and no pattern repeat) and buy it as extra fabric.

How long should my curtain rod be?

A good rule is window width plus 8 to 12 inches (20–30 cm) total — about 4–6 inches (10–15 cm) of overhang on each side — so the curtains can stack off the glass when open. Use the Rod Helper tab above: enter your window width and it recommends a rod length.

How do I calculate fabric for a bay window?

Measure the full curtain track or rod that spans the bay (not each window separately) and use that as the rod width — the fullness math is identical. If the bay has separate rods per section, calculate each section as its own window and add the totals.

What is the standard width of curtain fabric?

Most dress/curtain fabric is 54 inches (137 cm) wide; wide-width fabric at 108 inches (274 cm) is common for sheers and for wide panels sewn without a vertical seam. The calculator includes both presets plus a custom width option — always check your actual fabric’s cuttable width, which is slightly less than the bolt width after side hems.

How much extra fabric do I need for hems and headings?

Standard allowances are about 4 inches (10 cm) for the top heading and 4 inches (10 cm) for the bottom hem, plus about 1 inch (2.5 cm) per side hem. The calculator includes these by default and lets you adjust them — heavier fabrics or blackout linings sometimes want deeper bottom hems.

Can I use this calculator for sheer curtains?

Yes — choose “Sheer / voile” as the heading style. Sheers look best with high fullness (2.5x to 3x) so they drape softly instead of hanging flat. Pattern repeat rarely applies to sheers, so you can leave it at zero.

How much fabric do I need for a Roman blind?

Roman blinds need no fullness: fabric width is window width plus about 10 cm (4 in) for side returns, and cut length is the finished drop plus top and bottom allowances (the bottom needs a deeper pocket for the dowel). Switch to the Roman Blind tab above for a dedicated calculation.

What about curtains for sliding glass doors?

Treat the door like a very wide window: measure the rod or track width (usually door width plus overhang on both sides), pick your heading, and calculate normally. A standard sliding door is about 72 inches (183 cm) wide, so with pinch pleats expect roughly 4–5 widths. For wider sliding glass doors, consider splitting into 3–4 panels instead of 2 so each panel stays manageable — the total yardage is unchanged.

Is my measurement data sent to a server?

No. This calculator is 100% client-side: every calculation happens in your browser with JavaScript. Your measurements are never uploaded, stored, or tracked — there is no server to send them to.