Whether you want to hang new curtains or have a double frame installed, it is very important to understand what measures to take. Read the following instructions and have a tape measure or extendable ruler handy to learn how to measure a window, for any purpose.
Steps
Method 1 of 2: Measurements for Replacement Windows, Double Framing or External Shutters
Step 1. Measure the width at the three main points and take the smallest measurement as a reference
Use a tape measure or an extendable ruler to measure the width of the window opening at the base, middle or top. Take the smallest of these measurements as a reference length. Make sure you measure from the surface of the frame or post, not the shorter extensions used to secure the window.
An extendable ruler may allow you to take measurements more accurately. If you are using a tape measure, however, be sure to take into account the width of the tape measure, which is usually shown on the label
Step 2. Take into account the trim around the window, if any
The window could be surrounded by a plastic or aluminum post that accompanies the vertical sides. This piece will have to be removed before installing a replacement window, then measure its width and add it to that of the window opening. If you can't get access to the width of the liner, take 1.25cm as a general approximate measurement.
Step 3. Measure the height in the three main points
From the surface of the sill closest to the window, measure the height to the top of the window opening. Measure the left edge, the center and the right edge, and note the smallest result: it will be your height.
If the sill is at an angle, measure from the highest point, which is usually right next to the window
Step 4. If you are installing replacement windows, measure the depth as well
Measure the depth between the two stops that extend in front of the window frame. Try to measure at the smallest point, but it's not as important to measure at three different points as you do for height and width.
- If you can't open the window, measure the depth of each side and add them together. Alternatively, you can approximate by measuring the depth of the inner side and multiplying it by two. To the result of each of these methods, add the thickness of the glass panel, if you know it. A single pane of glass can vary in thickness, but about 3mm is a likely measure.
- Generally, there is a minimum depth to mount a replacement window or a double frame, but if the depth is greater than this minimum value, you will not need the precise measurement.
Step 5. Check if the window opening is rectangular
Measure the window opening from the top left corner to the bottom right corner and note the result. Measure the distance between the opposite corners (top right and bottom left) and compare it to the previous result. If these results are not the same, your window will not be square or rectangular. In this case you should let the manufacturer of the new windows or shutters know that the opening is "crooked" and provide them with the measurements.
Step 6. Be specific about where you took your measurements when ordering your windows or shutters
Some manufacturers of replacement windows, double frames or external shutters may require you to order products that are slightly narrower than the size of the opening, to make sure they fit properly. You can follow the manufacturer's instructions to reduce the size to the appropriate amount, or provide them with the exact size of your window opening. The important point to remember is that you need to be absolutely clear about the method you are using, as if both you and the manufacturer restrict the size of the window, you may get too small a piece.
Method 2 of 2: Taking Measurements for Curtains or Blinds
Step 1. Decide whether the product will be mounted inside or outside the window opening
Most of the curtains are fixed on the upper frame or on the wall above the frame, while the shutters are generally attached to the inside of the opening, at the point closest to the glass.
Step 2. If you need to mount the product inside the frame, measure the depth of the window opening
When measuring the depth of the window, it is vital to take measurements above any obstacles that may block the blinds. For example, if you have a double window, take measurements facing the outer window, not the back panel (which is normally the bottom half of the window). If there are handles or something else, it is advisable to measure the space in front of them.
If you are hanging half-length curtains or other short materials, you can ignore any obstacles that don't obstruct the part of the window covered by the curtains
Step 3. Measure the inside width in three different places and choose the smaller result
If you intend to hang the object inside the window, measure the internal width at the top, middle and bottom of the window opening (windows, whether new or old, are not always regular). Take the smallest result to make sure the blinds or curtains are the right size.
Step 4. Measure the internal height in three different points and choose the widest
Measure the internal height (from top to bottom) between the two internal edges of the window opening. Measure left, center and right. Take the largest of the three to make sure the hanging material reaches the bottom of the window.
If you are hanging short material from the top of the window you can also skip this step, since there is no need to make it reach the bottom of the opening. If you are hanging short curtains at half height, you should take the measurement of the height you are interested in, not the total one
Step 5. Measure the external width and height at the widest points
If you are hanging something outside the window, measure the height and width of the opening from the outside. You can take three equidistant measurements and choose the widest result, but if you intend to cover the entire window just take the measurements of the widest point. Add 1.25-2.5 cm to both the width and height to make sure it covers the entire window.
If you intend to mount the object above the window frame, measure the distance between the desired position and the frame itself. Add this measurement to the height of the opening
Advice
- Use a tape measure that also shows millimeters. It will allow you to have a more precise result.
- Use a tape measure or extendable ruler, not a regular ruler or measuring tape.
- If you can't measure both sides of the window yourself, have someone help you hold the tape measure.
