How to Measure Windows for Curtains (Step-by-Step Guide)

Instructions

Step 1: Decide Where You Will Mount the Hanging Hardware

When measuring a window for curtains, consider a few things before you get out the tape measure and pencil. First, determine where the hanging hardware, like the curtain rod, finials, and brackets, will be mounted.

See whether an outside mount will suit the room and your needs (this is where the curtains and curtain rods are mounted on the outside edge or above the window) or if an inside mount is better suited (this is where the curtain rod spans the width of the window opening and hangs inside the window frame).

Step 2: Place Outside Mounts Several Inches Above the Window

Remember that an outside mount with the curtain rod fixed several inches above the window will make the ceiling appear taller. The ceiling appearing taller can be great in a room that feels smaller. Also, an inside mount with curtains hanging inside the window frame will create a neat, clean look. Consider different options to decide which best suits the room or your needs.

Top Tip: Outside mount curtains will allow more light into the room when they are open as they will pull away completely from the window opening. Windows with a deep extended sill will suit an inside mount curtain well. The depth of the window allows the curtain to do its job without overpowering the look of the window.

When buying custom-made curtains, it is often recommended that you install the hanging hardware or measure the window before buying them. The width of the curtain rod and the height the rod can be placed above or in the window will determine the width of the curtain panels and the length of the drop and give you an idea of what curtains will best suit the space. Later we discuss what is best for pre-made curtains.

Using the ladder, measuring tape, and pencil, place the brackets for the curtain rail where you would like them to go and mark the holes with a pencil.

See steps two and three for details on measuring the width and length of the curtains for the correct placement of the brackets.

Step 3: Measure the Outside Edges for Hanging Space

For outside mount curtains, to determine how wide the rod or rail should be mounted, do the following:

• Measure the window width from the outside edges,
• For windows where two single curtain panels will open and hang alongside the window, add approximately 8 inches to each side to allow the curtains to open fully
• For windows where multiple curtains will open and hang alongside the window, allow more space dependent on the volume of the curtains.
• With the full-width measurement of the curtain rod determined, plan where the hanging brackets should go and mark those places.

Set the brackets a few inches above the window to complete the look. A curtain rail that sits too close to the window's top edge while allowing extra width to hold the open curtains will not look symmetrical, but adding a few extra inches on top will help.

Step 4: Measure the Window for Panel Width

If the window is near a corner in the room or another design feature that will not allow the curtain rod to extend much past the window frame, take this into account and measure equal amounts of space on both sides. In most cases, the window will look odd if one side of the rod extends further.

Then, use the curtain rod measurement to determine the width of the curtain panels you will use. Remember that a curtain needs to be two to three times wider than the curtain rod to give the fullness of appearance and to open and close easily.

If you have followed the method above and a curtain rod measures 50 inches, for example, the total width of the curtain panels, if the material were laid out flat, would need to be 100-150 inches.

For pre-made curtain panels, check the packaging for the panel width measurements and calculate how many panels will be needed to fit your rod comfortably. For custom-made curtain panels, communicate this measurement to the correct people.

Step 5: Measure the Window for Panel Length

There are six lengths to consider for a curtain. From longest to shortest, they are:

• An extra long drop hangs from an outside mount curtain rail to the floor, then the bottom edge 'puddles' on the floor.
• A floor-length drop hangs from an outside mount curtain rail to sit flush with the floor or at a recommended 1 inch above the floor.
• An 'Apron length' drop hangs from an outside mount curtain rail to six inches below the window sill.
• A sill-length drop hangs from an outside mount curtain rail to flush with the top edge of the window sill.
• A sill length drop hangs from an inside mount curtain rail to flush with the top edge of the window sill.
• A 'Café length' drop hangs halfway up the window on an inside mount curtain rail to flush with the top edge of the window sill.

Which length you choose is a matter of preference and styling, but when measuring the curtain's length, check the curtain's style as it may affect where to measure the curtain from.

For pleated curtains, such as pinch or double pleat curtains, you will need to start the measurement from the bottom of the rail where the rings or hooks connect to the curtain as the curtains hang below the rail. You will need to measure from the topmost part of the tab for tab-top curtains. For eyelet curtains, measure the curtain from the top edge of the ring, disregarding the material above it.

Top Tip: If you buy stock panels, they come in standard sizes; 84, 96, and 100-inch lengths are typical. If your desired length is less than these, alter them to fit the desired length.

Lastly, select the right curtain rod width for the window. With all these measurements in place, select a curtain rod or rail that is the correct width for your window or wall space, taking into account the extra width needed for curtains to hang alongside the window and if you will add finials or other embellishments to the end of the rod.

Top Tip: Remember that as much as 6-8 inches are usually needed for a single panel on each side of the window.

The material, whether wood or metal, is a matter of preference. However, note that the rod's thickness may alter your length measurements.

When measuring a window for pre-made curtains, it is often best to measure the window, order or buy the curtain and then install the rod or rail to allow for minor adjustments with all the hardware and curtains on hand for an actual measurement.