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How to Measure for Blackout Curtains? (Complete Guide)

Blackout curtains are a good choice for people with light sensitivity and those who work at night. They prevent all outside lights and provide a darkened room. However, for best results, you have to measure your curtains correctly before installing them.

So, let’s take a look at how you can measure your blackout curtains.

How to measure for blackout curtains?

To measure a blackout curtain, you have to measure the window at first. Then, measure the height and width of the window frame. Next, you need to extend the height and width of the curtain by at least 6 to 8 inches on both sides than the window frame. Thus, it will cover the whole of your window.

Correct measurement of blackout curtains is important. Because if you measure it wrong, it may not serve the whole purpose of blackout curtains. Here are a few steps for measuring blackout curtains:

  • At first, measure the rod you will hang your curtains on until the floor.
  • Then, measure the length of the window. After that, take length on both sides of the window. Note down the longest one.
  • Next, you have to measure the width of your window. It will be the base for the width of your curtain.
  • Once you finish measuring all sides, add 5 to 8 inches long along with the height of your window. In the case of width, multiply the width of your window frame by 2.4 inches. These will be your final measurements.

And this is how you can measure for your blackout curtains. While measuring, keep in mind that both the lengths and widths should be more than the length and width of the window itself.

How long should my blackout curtains be?

Unlike other curtains, blackout curtains must be longer than the window frame. Otherwise, it cannot prevent light from entering your room. That is why the longer your blackout curtains are, the better.

The standard here is to add a minimum of 4 to 5 inches to the length of your window frame. If you want a hanging curtain, you can add 2 to 3 inches with the length. However, it is not recommended.

For better results, try to use blackout curtains at least 8 inches longer than the window frame.

How wide should blackout curtains be?

Blackout curtains should be wide. They need to be wider than the window frame. As they block out sunlight, blackout curtains work best when they are single paneled.

Single panelled curtains will cover the window completely without any breaks. Thus, it will ensure complete darkness. A standard blackout curtain needs to be at least 2.5 times the width of the window frame.

For example, if the width of a window frame is 4ft, the curtain must be at least 10 ft wide.

Should blackout curtains touch the floor?

There is no specific answer to this question. It all depends on the style of your room and your preferences. However, keep in mind that floor touching curtains are better at blocking out the lights completely.

If you don’t like extra walls just below your curtains, go for floor touching curtains. As this type of curtains is very long, they completely block out all the lights. Hence, if you want a fully darkened room, choose this type of curtains.

However, keep in mind that floor touching curtains are hard to maintain. They are prone to more dust and get dirty often.

So, the bottom line here is that you can go for floor touching blackout curtains, but only if it matches your room’s theme and style. 

What sizes do blackout curtains come in?

As the function of blackout curtains is to block sunlight, there aren’t many sizes for them. All the sizes cover the window completely. Here are the size options:

Apron length:

These curtains lay a little below the windowsill. The width of these curtains is standard 42 or 52 inches. They are 63 inches in length.


Long blackout curtains lay much below the windowsill and just above the floor. They are usually 83 to 84 inches long, along with standard 42 or 52 inches width.


The extra-long curtains fall over the floor. They are usually 93 to 95 inches in length. Their width is the standard 42 or 52 inches.

How do you make homemade blackout curtains?

If you are low on budget and want to have blackout curtains, you can get DIY blackout curtains. They are very good at blocking sunlight and provide a dark ambiance to your room. And making your blackout curtains might be easier than you think.

Let’s take a look at how you can make blackout curtains all by yourself.

  • The first step is to take proper measurements of your window. Also, select a fabric for your curtain.
  • Organize all the other materials you will need for the project. You will need sewing needles, threads, blackout lining, measuring ribbon, scissors, and iron.
  • Now, cut the blackout lining and the fabric according to your measurements. Remember to keep extra space for the hemlines while cutting.
  • After cutting all the lining and the fabrics, iron all of them. It will remove all the wrinkles and help sewing. Also, fold the hemlines and iron them to make crisp folds.
  • Once all the ironing is completed, you can now start sewing. Start by sewing the blackout lining with the fabric. After that, sew all the hemlines.
  • After that, iron all the curtains and you are ready to hang them on your window.

So, this is how following a few simple steps, you can make your blackout curtains.

What is the best fabric for blackout curtains?

The purpose of having a blackout curtain is to block the sunlight. That is why, unlike regular curtains, blackout curtains require some heavy fabrics. And there are several fabric choices for blackout curtains.

Here are a few options that you can choose from:

Microfiber fabric:

This fabric is very effective in blocking sunlight. It can prevent almost 90% of the outside light from coming. As a result, microfiber fabrics are one of the most popular choices for blackout curtains.

Polyester fabric:

Polyester fabrics are a good choice if you are looking for durable options. These are very sturdy and durable. In addition, polyester fabrics are also easy to wash.

Flame retardant Fabric:

This fabric is perfect for commercial space. It is highly fire-resistant. So, it can provide your working space with extra fire safety.

Thermal insulated fabric:

If the temperature is an issue, you can use this type of fabric. Thermally insulated fabrics are woven in multiple layers with thermal insulating materials. As a result, they can control the temperature in your room.

How to measure for blackout shades?

Blackout shades are a good alternative to blackout curtains. To get the best out of your blackout shades, you will need to measure them correctly.

Decide whether you want to mount your shades inside or outside. After this, start measuring accordingly. Measure the width and height of your window frame. It could be either inside width or outside based on your mount style.

Take the width at the top, one at the bottom, and one at the middle. Finalize the smallest measurement here. Similarly, measure the height of your window frame measure from the left, from the right, and in the middle. Finalize the largest measurement.

However, you only need to measure the top for solar or exterior shades. If you want to mount your shades on the outside, add an extra inch or two on both sides.

How to measure for blackout blinds?

Just like shades, blackout blinds are another alternative for your room. Although blinds and shades have few differences, measuring for both of them is similar.

Like blackout shades, you can mount your blinds both inside and outside the window frame. Here, you need to measure the width and the height three times.

For width, take these measurements at the top, bottom, and middle. For length, these have to be on both left and right and in the middle.

In the case of an outside mount, you have to add two to three inches extra length on either side. In this way, you can measure your blinds.

The measurements of your blackout curtains are vital. Because if you measure them incorrectly, they may remain shorter than the window and let light slip through. That is why make sure to measure your curtains correctly.