How To Hang Curtains Check List
No.1 Fit your curtain track at least 4 inches over the top of your window. Assuming there is room, it will look better. I usually fit my curtain track at 5 or 6 inches over the top of the window frame. This allows the curtain header to sit over the wall so is not seen from outside. I think it just looks so much better.
No.2 The width of the track is the width of your window plus 5 or 6 inches past both sides. This allows your curtain to pull back of the window allowing maximum light to enter the room.
Sometimes I would make the curtain track a few inches wider if your curtains are made of thick fabric or have heavy blackout lining. If you hanging curtains on a very wide window. Such as a patio door or a large bay window. then I would add between 8 and 10 inches to each side of your window measurement. These types of windows have a lot of fabric in the curtains. So need more space to pull off the glass area.
To work out how wide each curtain panel should be (assuming a pair). You need to allow for each panel un-gathered to be appoximately the same with of the curtain rod. Give or take a couple of inches. This allows the curtains to have enough gathered fabric when hanging over your window.
So at least 2 times your track width for pencil pleat curtains. If you are hanging pinch pleat curtains on your window. Then you will have between 2 1/4 to 2 1/2 times your track width in your curtains.
No.3 Sometimes it's easier to get accurate width and length measurements with your chosen curtain hardware already fitted in place over your window. I recommend you use a step ladder to get accurate measurements when having floor length curtains. I usually measure from the floor up to the top edge of the curtain track.
No.4 if If your curtains are not to the floor then hook your steel tape measure on the top edge of the track. This is so the track is not seen when the curtains are closed. Then measure down to where you want your curtains to finish. Maybe to just go to the window sill or a few inches past the window sill. This gives you the finished curtain drop (length).
No.5 Use a pad and pen and write down each size as you measure. Then go back and double check your sizes to make sure there are no errors. Even better ask someone else to check for you.
If you are measuring for very wide or long curtains. Then I would definitely have some one help you by holding one end of the tape measure while you pull out the tape and measure more accurately. Then swap over do the same again. It's called a "sanity check" :-)
Amazing how he mind can play tricks on you. That's how to measure curtains that fit perfectly.
I hope it helps you get the right sizes for your new curtains :-)