How To Calculate Pleats
Pleats make regular curtains look so much more ornamental and can add an accent to a bedroom or living room without too much effort. Certain pleats also add a fuller look to thinner fabrics and can make simplistic rooms look a little bit more formal. One of the most common pleats are pinch pleats, and they aren't as complicated or as intimidating to create as they first seem. But making those pleats requires a bit of planning, knowing the right measurements and making sure you have enough material for putting the curtain together and hanging it up on a window.
Window Measurements
Measure the width of the window. Don't just size the glass – measure from the outside casing to the other outside edge of the window. Also, determine the length by measuring from the curtain rod to the window sill. Be sure to write down all of the measurements so there aren't any miscalculations for the next steps.
Be sure to add 4 to 5 inches to those measurements to account for the curtain overlap in the center when the curtains are closed. If you don't want too much of an overlap, only calculate in around 3 inches.
The Pleats
Tally the number of pleats that will be on the window curtain. For example, there can be six pleats. Divide the window length by the number of pleats, then calculate how big you'd like the pleat to be. Add another few inches for the fold of the pleat.
If you'd like there to be six pleats, measure how long you'd like each pleat to be. For example, if you'd like each double pinch pleat to be around 4 inches, add another 2 inches for each fold since they should be half of the length of the pleat. So if you're calculating six double pinch pleats, add 24 inches to the width of the window.
If you'd like to make the pleats larger or smaller than the example above, calculate it by multiplying the desired number of pleats to the length of the folds, then add that to the width of the window.
Added Curtain Measurements
Also, add an extra few inches for the top of the curtain to fit into the rod and for the hem at the bottom. To make sure you've calculated the correct numbers, measure the circumference of the rod with a tape measure, and then add an extra inch or an inch and a half to the length of the rod's circumference. This will add more ease and flexibility when it comes to putting the curtain on the rod and hanging it up. It's more important to have space at the top than a hem, but having a decent hem makes the curtain look a lot neater and helps avoid frayed ends.
It's always best to calculate a little bit more fabric and cut it off at the side, then hem the curtain or pin and fold it back. The alternative is to calculate too little fabric and have an awkward looking window.
Added Help
To make sure that all of your calculations add up, there are online pleat guides that can help adjust or confirm your measurements.