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How to Measure Windows for Curtains

How to Measure Windows for Curtains

Even if you intend to purchase ready-made curtains or customize your design. Without precise window measurements, you won’t be able to get the perfect curtains for your space. Getting an accurate measurement is a first and most important step.

Most people struggle with getting accurate measurements. However, this is a fairly straightforward task and is quite easy to measure. When you’re trying to cover a lot of windows, it might get a bit confusing, but if you keep track of the measurement it won’t be too difficult.

Just in case you are not willing to get yourself into this hassle, you can simply hire an expert who will charge around $75-$100 for the overall measurement. For your convenience, here we’ve broken down the measurement process into the simplest form possible.

Tools Needed

  • Measuring tape
  • Ladder or stool
  • Writing Pad
  • Pencil 

Choose Mount Type

Start by deciding whether you want your curtains to be inside or outside mount

  • Inside mount: The drapes or blinds are fitted inside the window framing, 
  • Outside mount: The curtains or drapes are installed above the window frame close to the ceiling.

Measuring for Inside Mount

measuring for inside mount
  • For the inside mount measure edges of the window frame.   
  • Take three measurements of the window’s width in different places to make sure it’s square or not. If the measurements are unequal, the shortest one will be utilized.
  • Repeat the same process for measuring height as well if the measurement is uneven, the shortest of the three measurements should be chosen.

Note: If you prefer an inside mount, make sure that the window locks or handles do not interfere with the blind and that light may pass through gaps on both sides.

Measuring for Outside Mount

measuirng for outside mount
  •  For the outside mount, measure the width from one side of the architrave to another or the outer edge outside the window frame
  • For height measure from the top of the architrave edge to the bottom of the sill or the floor.

Determine Rod Length 

Determine Rod Length 

The length of your curtain rod also plays a vital role in the measurement of the curtain. Curtain rods are usually placed one foot below the ceiling level and 3 to 6 inches above

 the window frame. We take our measurements from the top of the rod to the window sill or below as you prefer. Since the rod can be mounted inside, below, or above trim mount so where you install will affect the length.

NOTE: while measuring the width of the rod measure between the finials from one end to another. Don’t include the rod cover balls or decorative finials.

Inside mount rod: For a snug fit, choose curtain rods with protected end covers and an extendable design. For this modern style, window treatments should be roughly the same width as the interior of the window.

For example: If the width of your window is 30 inches. Get a rod size of 30 inches. 

Below trim mount: If your window frame has gorgeous molding at the top, consider placing the curtain rod just below the trim. This is the best way to display your molding’s craftsmanship. Look for a curtain rod that reaches at least 3 to 5 inches beyond the width of the window on either side for a full look.

For example: If your window width is 30 inches. Rod size should be 33-35 inches.

Above trim mount: Curtain rods should be placed around 6-12 inches above the window frame. However, it all depends on the amount of space between the top of your window and the ceiling, as well as the overall look you want to achieve. The larger your window seems the taller and wider your curtain rod is placed. Add 4 inches to each side after measuring the width of the window.

For example: If the width of your window is 30 inches. Your rod size should be 38 inches.

Measuring Window Length

measuring window length

Now you need to decide how long you want your window length to be. 

  • Above sill: Curtains hang typically 1cm above the window sill
  • Below sill: Curtain hangs 15cm below the sill. 
  • Floor-length curtains: Curtains will either end less than a quarter-inch above the floor or will slightly touch the floor.
  • Curtains that puddle: Curtains strike the ground and 2-3 inches of the curtain is left on the ground. 

Once you decide the length measure from the curtains rod to the above, below, floor, or puddle as per your preference.

Measure Window Width

measuring window width

You can use the single, double, or as much pair of curtains in your window depending upon the look you are trying to achieve. It is recommended to buy a curtain that is 2-3 times the width of your window

For example: If the width of the window is 35 inches get the (35 x 2 = 70’’) Your curtains should be 70inches minimum.

Note: If the curtain width is to be more than 50 or more inches. Get 2 panels or 1 pair of curtains. The rule applies as it gets exceeded. For example, 100 inches width gets 4 panels.


You need to consider minor details to get the perfect measurement. You might get a little confused so it is recommended to clearly note down each measurement. This will make the whole process easy for you. Once you are sure about the measurement you can go for further steps like buying the rods and choosing the correct fabric and length of the curtain.