Measuring curtains might seem a bit discouraging at first, but in reality, this task is quite simple and straightforward. The following article will provide you with detailed instructions on measuring both the inside and outside of the window frame.
Steps
Measuring Inside-Mounted Curtains
Inside-mounted curtains are installed within the window frame for a neater appearance. If the window depth is suitable, this curtain installation method is the most common.

Ensure accurate measurements. If the window is designed with a deep recess, installing curtains inside the frame will give the window a clean, finished look. However, measurement errors can lead to complications.

Measure the width. Measure the width of the window recess at three points: the top, middle, and bottom. Make sure to stretch the tape measure to the inner edges of the recess. Record the smallest measurement, as this is the one you will need to use.
Measure the height. Measure the height of the window recess at three locations: the left, center, and right. Ensure that you stretch the tape measure to the inner edges of the recess. Record the largest measurement, as this is the one you will need to use.
Measuring Outside-Mounted Curtains
Outside-mounted curtains are installed on the wall outside the window frame. This is not the preferred method, but if the window recess is not deep enough, this type of installation can be used.
Identify the curtain rod placement. Curtains should be mounted 1.5 to 3 inches above the window frame.
Measure the height. Measure from the intended rod position down past the window edge by 2–4 inches. This extra length helps block light and ensures privacy.
Measure the width. For the width of any curtain, take precise measurements and add 2–4 inches on each side.
Tips
- Always use a steel tape measure for accurate measurements.
- Always measure at least twice before recording the final dimensions.
- Always label which measurement is width and which is height. Many people confuse the two due to carelessness, so note width first, followed by height (WxH).
What You'll Need
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Folding ladder
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Metal tape measure
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Pencil
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Paper