How to Calculate Fabric for a Curtain
To calculate the fabric for a curtain, multiply the rod width by a fullness ratio (1.5 to 2 for simple gathering tape, 2.5 to 3 for a fuller heading) to get the fabric width. For the height, measure from the top of the rod to the floor, then add the hems, usually 15 to 20 cm at the top and 10 to 15 cm at the bottom. Divide the fabric width by the roll width to find the number of widths (drops).
Calculating the fabric and sewing take time and precision. Kurtens makes curtains custom to the exact centimetre, delivered ready to hang, with no calculation or cutting.
The 3 starting measurements
Three measurements form the basis of the calculation. Take them with a tape measure, rod fitted.
- Rod width, from one end to the other. It is the basis of the fabric-width calculation, not the window width.
- Desired height, from the top of the rod to the chosen bottom point: to the floor, just touching the floor, or to the window sill depending on the style.
- Roll width, the width of the fabric roll, often 140 cm. It determines the number of widths to join.
Calculate the fabric width
A curtain must be wider than the rod to hang in folds. You apply a fullness ratio to the rod width:
| Heading type | Ratio | Effect |
|---|---|---|
| Simple gathering tape, flat pleats | 1.5 to 2 | Light folds, understated |
| Eyelets, wave pleats | 2 to 2.5 | Regular folds, structured |
| Pleated heading, dense gather | 2.5 to 3 | Full folds, elegant |
Fabric width = rod width x ratio. For two curtains meeting in the centre, this total splits into two equal panels.
Calculate the fabric height
To the desired height, add the hems: count in general 15 to 20 cm at the top (for the heading and turn-over) and 10 to 15 cm at the bottom. Fabric height = desired height + top hem + bottom hem. If the fabric has a pattern repeat, add the height of one repeat per extra width.
Calculate the number of widths and the total fabric
Divide the required fabric width by the roll width (often 140 cm) and round up to the next width: that is the number of widths (drops) to sew side by side. Total fabric = number of widths x fabric height (hems included). Allow a small margin for pattern repeats and adjustments.
Example. A 200 cm rod, eyelet heading (ratio 2), desired height 250 cm. Fabric width = 200 x 2 = 400 cm, that is 3 widths in 140 cm roll width. Fabric height = 250 + 18 + 12 = 280 cm. Total fabric = 3 x 2.80 m = 8.40 m of fabric, excluding the repeat margin.
Skip the calculation: ready-to-hang custom
Calculating the fabric, buying it, cutting and sewing take time, equipment and precision: one mistake in the ratio or the hem and the drape is ruined. Custom removes this step. Kurtens makes curtains custom to the exact centimetre, in a range of colors and fabrics, delivered hemmed and ready to hang. You give your measurements, the curtain arrives finished. To take your measurements, see the measuring guide and the heading guide, then the Kurtens custom curtains.
Frequently asked questions
What fullness ratio for a curtain?
Count 1.5 to 2 for a simple gathering tape with flat pleats, 2 to 2.5 for eyelets or wave pleats, 2.5 to 3 for a pleated heading with dense gather. The higher the ratio, the fuller the folds. It is applied to the rod width.
How to calculate the width of a curtain?
Multiply the rod width (not the window) by the chosen fullness ratio. A 200 cm rod with a ratio of 2 needs 400 cm of fabric in width, split into panels depending on the number of curtains.
How many metres of fabric for a curtain?
It depends on the rod width, the fullness ratio, the height and the roll width. For a 200 cm rod, eyelets and 250 cm height, count about 8.40 m in 140 cm roll width. Add a margin for pattern repeats.
What margin should you allow for curtain hems?
Count in general 15 to 20 cm at the top for the heading and turn-over, and 10 to 15 cm at the bottom for the hem. Add these margins to the desired height before calculating the total fabric.
How to avoid calculating the fabric for a curtain?
By ordering custom: you give the width, the height and the heading type, the curtain arrives hemmed and ready to hang, with no fabric buying or sewing. Custom to the exact centimetre removes all the calculation.
Calculating the fabric takes precision; custom removes it. Have your curtain made to the right measurements as a Kurtens custom curtain, delivered ready to hang.
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