How-to - DIY Curtain Calculations

Curtains can be costly to buy or have custom-made, especially if you want quality materials and workmanship. If you can sew a straight line and take some measurements, you can make your own at a fraction of the cost. Below you will find the steps to calculate the amount of fabric you need to sew your own curtains.

  

Measurements will be taken in inches and converted to yards or meters. The two styles of curtains typically sewn are gathered or pinch pleats.

!  There are 36 inches in one yard and ~ 39 inches in one meter.

1.      Decide on the style of curtain you wish to sew – gathered or pinch pleats

1.1.    Gathered curtains have a multiplication factor of “2”

1.2.    Pinch pleated curtains have a multiplication factor of “2.5”

2.      Measure your window frame width from wall to wall

2.1.    Add 10 inches (25cm)to the measured width

*   This will allow 5 inches (12.5cm) per side for seam finishing etc.

3.      Measure your window frame height from top to bottom

3.1.    Add 12 inches (30cm)to the measured height

*   This will allow finishes of 5 inches (12.5cm) for the header and 7 inches (17.5cm) for the hem

4.      Choose your fabric and measure the width from selvage to selvage

! Most standard fabric widths are 36, 45, and 54 or 60 inches; specialized drapery fabric can be wider.

5.      Determine if the fabric has an obvious pattern that repeats or a “nap”

*       No – Proceed to Step 6

*       Yes – Measure the length of the repeat interval (ex. The pattern repeats itself every 20 inches) and proceed to Step 6

6.      Multiply the total width measurement in Step 2.1 by the multiplication factor for your  chosen style of curtains in Step 1

7.      Take the number in Step 6 and divide it by your fabric width

1.1.    Is the number a whole number? (ex. 5 or 5.1)

*       Yes  – Proceed to Step 8

*       No  – Round the number up to the next whole number and proceed to Step 8

! The number in Step 7 will be the number of fabric panels or pieces required to cover your window from the fabric width and style chosen.

8.      Determine the total length of fabric required in inches

1.1.    For fabrics with no obvious pattern repeats or a "nap", multiply your number of fabric panels in Step 7 by the total height measurement in Step 3.1

1.2.    For fabrics with a pattern repeat or "nap", divide the total height measurement in Step 3.1 by the repeat interval measured in Step 5 (this will determine the number of pattern repeat intervals per fabric panel)

1.2.  

1.2.1. Is the number a whole number? (ex. 100 or 100.2)

*       Yes  – Proceed to Step 8.2

*       No  – Round the number up to the next whole number and proceed to Step 8.2

2.       Multiply the whole number by the repeat interval in Step 5

3.       Multiply your number of fabric panels in Step 7 by the number in Step 8.2

9.      Convert the total inches of fabric required for your curtain project to the appropriate measurements.

1.1.    For fabric requirements in yards, divide your number by “36”.

1.2.    For fabric requirements in meters, divide your number by “39”.

10. Round the converted number up or down for fabric purchase.