It’s one of those things that always seems a bit complicated but it’s actually quite simple to measure how much fabric you will need for your curtains. It all depends on the type of heading you want your curtains to have, and whether your fabric has a repeat.
First of all, lets explain what a repeat is. It is simply how frequently a pattern recurs down a length of fabric. You need to know this as properly made curtains need to have the pattern matched when you join the widths together. Much like wallpaper – once you have pasted one length on the wall, you would slide the next width up or down to match the patterns together and make an invisible join. So plain and striped fabrics always have a “0” repeat, and any kind of pattern will always have a repeat which you need to know to work out your lengths.
Next – you need to work out the widths. As a basic rule, measure the width of your window opening or the “glass size” and then add on 20cm at each end to give your curtains somewhere to hang when they are open. This should be your “pole width”. Take your pole width, and multiply it by 2 for pencil pleat or tab top heading curtains, or 2.5 for French pleat, box pleat, Goblet or most other heading. You then need to divide this number by the width of your fabric. Round that number up to the nearest whole and that will give you how many widths of fabric you need.
Next work out the length from the curtain ring to the floor or sill – wherever you want to stop. If you have a plain fabric simply add 20cm onto this to allow for your top and hems and multiply this number by the amount of widths (as calculated above).
If your fabric has a repeat, round up the length to a multiple of the repeat measurements i.e. 64cm repeat and required drop is 200cm. I would need 4 multiples of 64cm to match the pattern and have enough length – each width would have to be cut at 256cm.
Our SewSimple curtain kits will work all of this out for you so no need to worry if you didn’t get that first time around!