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Blind Size Calculator

Table of contents

What is a window blind?How do I correctly measure my window for blinds?How to use our blind size calculatorHow to manually calculate your window blind sizeWhat are the standard blind sizes available in stores?What is an outside mount window blind?How to choose the correct mounting style to suit your windowFAQs

Do you need a blind size calculator to help you to figure out the correct size blinds to buy to replace those old ones? 🙌 You have come to the right place.

Keep reading to learn:

  • What is a window blind;
  • How to measure your windows for blinds;
  • What are the standard size blind sizes available;
  • How our blind size calculator works;
  • How to figure out what size blinds you need;
  • What custom size blinds are;
  • How to cut blinds to size; and more.

Are you thinking of buying curtains too? Our curtain size calculator is just what you need.

What is a window blind?

A window blind is a type of window covering made of vertical or horizontal slats. These slats are made of some hard material. These include wood, plastic, and metal.

Typically blinds have a control at the side that allows us to open or close the slats to let light in.

How do I correctly measure my window for blinds?

Whether you are using an inside or outside mount, this is how you measure your windows for blinds:

  1. Measure the width from the inside of the frame at the top, middle, and bottom.
  2. Measure the height from the inside frame at the left, right sides, and the center.
  3. Record all of these measurements.

ğŸ”Ž An inside mount window blind sits within the window frame while
an outside mount blind extends over the window frame.

How to measure your window for blinds

How to use our blind size calculator

Our blind size calculator is pretty straightforward to use. Simply:

  1. Choose your preferred hanging style.
  2. Measure the width of your window from the inner edge of the frame at the top, bottom, and middle.
  3. Measure the window's height from the inner edge of the frame on the right, left, and center.
  4. Enter the measurements in their respective fields in the calculator.
  5. Our blind size calculator should now display the best measurements to suit your needs below the calculator.

Are you interested in other calculators that will help you to decorate your home? Check out our tablecloth size and bathroom mirror size calculators.

How to manually calculate your window blind size

Depending on the mounting style you choose, the way you calculate your window blind size differs. For inside mount blinds:

  1. Once we have the top, middle and bottom widths, we need to choose the smallest measurement for the width of your blind.

  2. Determine the length for the left-most height, right-most height, and the center of your window.

  3. Use the longest measurement for the length. If you do not wish to have the blind touching the bottom of the window sill, subtract 1/4th of an inch.

Outside mount blinds overlap the edges of the window. So while we may use the same system to measure, we do not use it in the same manner as we did for the inside mounted blinds. For outside mount blinds:

  1. Use the longest width of the three you measured. Add 3 inches to this. This is because we want our blinds to overlap by 1.5 inches on either side.

  2. Using the most extended length, add 1.5 inches. This 1.5 inches is necessary because we want the blind to overlap by 1.5 inches at the top.

What are the standard blind sizes available in stores?

There are no standard blind sizes. The window blind sizes available are cut to suit the basic types of windows, of which there are three primary ones, and they also come in different sizes.

The main types of windows are:

  • Picture windows that are 12 to 96 inches high, 24 to 96 inches;

  • Sliders that are 24 to 60 inches tall and 36 to 84 inches wide; and

  • Double hung windows that are 36 to 72 inches high and 36 to 84 inches wide.

Store window blinds vary in length but generally cater to these measurements. However, if you have oddly shaped windows in your home that do not adhere to the measurements laid out here, you may have the blinds cut to size or have custom-size blinds made to suit your needs.

What is an outside mount window blind?

Difference between inside and outside mount

An outside mount window blind is one that we install over the frame of the window. They can make your window appear longer or cover faults.

How to choose the correct mounting style to suit your window

Inside mount is the most common style of blind used. However, there are instances in which an outside mount would suit your needs better. To decide when an outside mount is better for your window, consider the following things:

  • The uneven-shaped window: Measure and compare the length of the diagonal of your window. If the difference is significant, more than 1 inch, the outside mount will suit your needs better.

  • The temperature is another thing to consider when choosing the mounting style for your window. Outside mount blinds are better for hot temperatures. They reduce the heat in the room.

  • You wish to make your windows appear bigger than they are. An outside mount can conceal your window trim and make them appear bigger than they are, so if this is your desire, an exterior mount style is just what you need.

  • There are obstructions inside your window frame. These will prevent an inside mount blind from sitting properly within your window frame. In such an instance, it is better to choose an outside mount.

  • When you wish to block out light completely, an outside mount suits your needs much better.


What are custom size blinds?

Custom size blinds are blinds created to fit a particular window and have no bearing on the standard sizes or whether they can fit other similar windows.

What size blinds do I need for 34.5 inch long window?

37 inches long.

Assuming that you wish to have an outside mounted window blind, the length of your blind should be:

34.5 + 1.5 = 37 inches long.

How do I figure out the correct size window blind I need?

Assuming that you wish to use an inside mount window blind that will touch the window sill at the bottom:

  1. Measure the width of your window from the inside of the facing at the top, middle, and bottom.
  2. Choose the smallest width.
  3. Measure the height of your window inside the facing at the right, center, and left.
  4. Choose the most extended height.
  5. The answers from steps 2 and 4 are the correct measurements.

Mount type

How to measure for blind.

Width measurements

Height measurements

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