How Much Fabric Do You Need for Curtains?
For a pair of curtains on a 60 in rod, 84 in long, at 2× fullness, buy 8 yd of 54 in wide fabric. You cut 3 pieces, each 96 in long, and each curtain uses 1 1/2 of them. The calculator above works this out for your window; the rest of this page explains each step.
How to Measure for Curtains
You need two measurements:
- Rod or track width. Measure from end to end, not counting the decorative ends (finials).
- Drop. The drop is the finished length of the curtain: from the top of the rod, or from the rings if it hangs from rings, down to where it should end, such as the sill or the floor.
Some UK calculators also say “drops” for the number of widths to cut.
How to Use the Curtain Fabric Calculator
- Enter the rod width and the finished length (drop).
- Choose the number of panels. A pair is one panel on each side of the window.
- Choose the fullness (see below).
- Choose your fabric width: 54 in · decor for most curtain fabric, or Custom.
- Add the pattern repeat if your fabric has one, and turn on Add lining for lined curtains.
The result shows how much to buy, how many widths to cut and how long, and a drawing of each panel. The heading, hem and side allowances are under More options.
What Is Curtain Fullness?
Fullness is how much wider the fabric is than the rod, so the curtain hangs in soft folds instead of lying flat. At 2×, a 60 in rod needs 120 in of fabric across the panels, before hems. Common choices:
- 1.5× (light): grommet curtains, with rings set into the top.
- 2× (standard): most curtains.
- 2.5× (full): pleated drapes.
- 3× (very full): sheers.
Your real fullness
Fabric comes in whole widths, so the calculator rounds up to the next whole or half width, and your curtains usually come out a little fuller than you chose. In the example, each curtain needs 66 in of flat fabric: half of 120 in, plus 3 in for each side edge. One width (54 in) is too narrow, so each curtain gets 1 1/2 widths, 80 in once joined. That makes them about 2.5× full, and the result tells you so.
Widths and Half Widths
A width is one piece of fabric the full width of the bolt, cut to length. Widths are sewn side by side to make each curtain, with a 1/2 in seam allowance on each side of every join. Curtain fabric is usually joined with its selvages (the firm woven edges) left on, so use the width the shop quotes.
With Allow half widths on, one width can be cut in half lengthwise and shared between a pair. That’s why the example needs only 3 widths and 8 yd. With whole widths, it needs 4 widths and 10 3/4 yd, and the curtains come out about 3.4× full.
Allowances: Heading, Hem and Sides
Each width is cut longer than the drop, to leave fabric for the top and bottom:
- Heading: the top edge, folded over for the rod, rings or curtain tape. The calculator starts at 4 in. Tape headings need about 2 in; rod pockets need more.
- Bottom hem: 8 in, for a double 4 in hem (folded twice). Short curtains often use a double 3 in hem, which takes 6 in.
- Side hems: 3 in for each side edge, for a 1 1/2 in hem folded twice.
So each cut is 84 in + 4 in + 8 in = 96 in.
Calculators don’t all use the same allowances. Some add about 8 in to each cut for the heading and hem, others about 13 in, and some leave out the side hems, which then come out of the fullness. That’s why curtain calculators often disagree by a few inches per cut. You can change every allowance under More options.
Heading tape and buckram
Heading tape is a strip sewn across the top of a curtain with cords running through it. Pulling the cords gathers the fabric into pleats, such as pencil pleats. Buckram is a stiff fabric strip sewn inside the heading to hold pinch pleats and similar pleats in shape. Which one you use changes the heading allowance, so check it under More options.
Pattern Repeat
If the print repeats down the fabric, every width has to start at the same point in the pattern so the print lines up across the curtains. The calculator rounds each cut up to whole repeats and adds one extra repeat, so you can start the first cut where you want the pattern to sit (for example, a full motif at the hem).
With a 27 in repeat, the 96 in cut becomes 108 in (4 repeats). The example then needs 3 cuts of 108 in plus one extra 27 in repeat, 351 in in total, so you buy 9 3/4 yd instead of 8 yd.
Lined Curtains
Lining is a plain fabric sewn behind the curtain to block light and protect it. Turn on Add lining and choose its width; most curtain lining is 54 in wide. The calculator works out the lining’s own widths, cut to the same length but without the pattern repeat. For the example, that’s 3 widths of 96 in, so you buy 8 yd of lining.
Making a tablecloth or napkins to match? The fabric calculator works out how much fabric you need for any set of pieces.