Many times people ask us how to calculate the fabric needed to cover a window or a balcony door.

How high should the curtain be placed? What allowances should we leave right – left of the window?

How do we calculate the final height of the curtain?

Of course the right choice should highlight the space aesthetically and practically depending on its use and needs.

However, since the topics are a lot from selecting the right fabric to the measuring and its installing, we will deal with each theme one at a time separately.

So let’s see how we calculate the right measures of an opening window or balcony so that we know exactly how many fabric will be needed.


Curtain poles (if already installed)

We measure the pole from a support to the other without the decorative edges.

If we have a curtain track, we measure from side to side. If the track covers the entire surface of the wall while the window is much smaller, we have to decide how much we want our curtain to cover right and left of the window.

If we have no pole or track installed yet, it is the best choice to leave 10-20 cm allowances right and left, if possible.


In case we have poles with rings, we measure from the bottom part of the ring to the floor, we deduct 2 cm if we want the curtain to be just up the floor. We add 5 cm if we want the curtain to touch softly the floor or 10-15 cm if we want the curtain to drag on the ground.

In case we have tracks, we measure from the bottom of the track and we deduct 2 cm or we add depending on how much we want the curtain to hang up or to lean on the floor.



When finally we sew the curtain, we need to pay attention to the allowances that we will leave above the tape. The fabric needs to cover the plastic part on the rings and on the tracks where we hang the curtain.

We usually calculate 2 cm extra height.

Let’s see an example

The width between the supports is 1,60 m.

The height from the bottom of the rings to the floor is 2,20 m.

We want to sew a ruffled curtain.

We measure 1,60 x 2 times = 3,20 m + 10 cm for sewing lateral hems. Total fabric needed 3,30 m.


If we want the curtain to end a little bit up to the floor, we measure 2,20 cm – 2 cm = 2,18 cm and we add 2 cm to cover the rings, so 2,20 cm final measurement.

We sew the tape 2 cm from the top edge of the curtain.

For sure there are many curtains’ styles with different measurement procedures, but the general rule is to multiply the opening of the window or the balcony door for two (2) or three (3) for more pleats