5 Steps to Measure a Window for Curtains

Are you looking to install new curtains for your home? This is arguably one of the most exciting interior décor projects—well-done curtains can do wonders for any room. Getting the right measurements can be a bit tricky though. But, not to worry—I will show you how to measure a window for curtains like a pro!

What to think about when measuring a Window for curtains

Not content with just window film for day and night privacy? Dress up your windows with the right curtains not just for privacy but also for extra elegance.

A lot goes into installing the perfect curtains. Before getting busy with your tape measure, there are a few things to keep in mind.

  • Rod placement: Is the window track or rod inside or outside the window frame? How far above the window frame is the rod? The placement will influence how you will measure the width of the curtains.
  • Curtain Length: The drop, which is the vertical length of the curtain, can vary depending on function and personal style. Whether you want the curtain to hang just above the sill or you prefer puddling at the bottom, you’d need to measure accordingly.
  • Curtain style: The perfect curtain should have just enough gathers. Examples of gather styles include pencil pleats, double pinch pleat, triple pinch pleat, and eyelet gathers. To achieve the right amount of gathers, you’d need accurate length and width measurements.

A step-by-step guide to measuring a window for curtains

Now that you know how you want your curtains to look, it is time to get down to the fun part, which is getting the correct measurements!

Things you will need

  • Steel tape measure
  • Stool ladder
  • Pen and notepad

Step 1: Measure the window width

Measure the window width

Start by measuring the width from the outside edges of the window. Place one end of the tape measure on the outer edge of the window frame and measure across to the other end of the frame. Write down the measurements in inches or centimeters.

Step 2: Decide on the rod placement and length

If you want to install a rod or pole on your windows, you can place it above, inside, or below the window trim.

For longer curtains, install the rod above the trim. To determine the correct rod length, add 8cms to each side of the width measurements you had taken earlier. For example, if the width of the window is 120cms, the rod length should be 136cm i.e. (120+8+8cm).

If you prefer to place the rod below the window trim, add 6cm to 8cm to the width measurement to buy the right rod length. Lastly, for rods placed inside the window trim, their length should match the width of the window.

Step 3: Account for finials and brackets

Account for finials and brackets

Add about 20cms to each side of the window to allow for finials and brackets if your windows have rods or you plan to install them. This will ensure that your curtains line up gracefully along the length of the rod. For example, if the window width measures 120cms, your curtains should measure 140cms.

If you are placing your curtains within the window frame or on a recessed window, you do not need to add finials measurements to the existing window width measurements.

Step 4: Keep in mind your preferred curtain type

The correct rod and width measurements ensure that your curtains not only fit the window and open wide but that they also come out with the perfect pleats.

To buy the correct size tab-top style curtains, multiply the width of the window by 1.5. For example, for a window measuring 120cm widthwise, the ideal curtain length would be about 180cms.

If you prefer pencil pleated curtains, take the width of the window and multiply it by 2 to get the correct size for your curtains. Apply the same process to measure for the right size eyelet curtains. In both cases, your curtains should measure about 240cms for the perfect gathers.

Step 5: Choose the appropriate curtain length

When deciding on the length of the curtain, you have three options. The first option is the floor-length curtain, which should end about 1.25cm above the floor. For the puddling effect where the bottom of the curtain drapes the floor, add a few more centimeters to account for extra fabric.

Secondly, you might opt for an above the sill length, where the curtain hangs 1cm above the windowsill. The last option is having the curtain length extend about 15cms past the windowsill.

Keep in mind both functionality and style when choosing the length of your curtains. Floor-length types ooze with elegance but might not be very practical on a window that you use frequently. On the other hand, above and below sill curtains can withstand frequent drawing and shutting.

Step 6: Take the correct curtain drop measurements

Take the correct curtain drop measurements

After deciding on your preferred curtain length, measure the drop. The drop is simply the vertical length of the curtain. How you measure the drop will depend on the method you will use to hang your curtain.

If your curtain will hang from a pole in eyelet style, place the tape measure at the top of the pole and measure down to your chosen curtain length.

Alternatively, for pleat style curtains that will hang using rings, measure the drop starting from the eye of the curtain rings down to your preferred length.

Lastly, if your windows have a curtain track, measure from the top of the track down to your chosen curtain length.

Pro tips for measuring a window for curtains

  • Take three measurements for the window width and length. This is because window frame measurements usually vary at different points. For the width, measure the top, middle, and lower sections of the frame. Use the smallest measurement if measuring from the inside of the frame and the largest if measuring from the outside. For the length, measure the left side, middle, and right side. Use the longest measurement.
  • Keep windows 2cm-3cm above the radiator to prevent the heat from escaping behind the curtain.


Curtains do not always come cheap, making it important to get the measurements right from the get-go. Use the tips provided above and you will be well on your way to gracing your windows with beautiful, right-sized curtains.

Do you have other hacks or tips for measuring for window curtains? Let us know in the comments and do not hesitate to leave your questions if you have any!

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