When it comes to installing window blinds, one of the most important steps is getting your measurements right. Accurate measurements ensure that your blinds will fit perfectly, function properly, and complement the overall design of your space. At Alpha Decor, we understand that taking the right measurements can be intimidating, but with the right approach, it can be a simple and straightforward task.

In this ultimate guide, we’ll walk you through everything you need to know about measuring windows for blinds to help you achieve a flawless installation. Whether you’re installing blinds for the first time or replacing old ones, these steps will ensure that your blinds are the perfect fit for your windows.

Step 1: Decide Between Inside or Outside Mount

Before you begin measuring, the first decision you need to make is whether to mount your blinds inside or outside the window frame. This choice significantly affects the way you measure and the final appearance of the blinds. Let’s break down the difference:

• Inside Mount: Blinds that are mounted inside the window frame offer a sleek and clean look. This type of installation allows the window trim or molding to remain visible, which adds a decorative touch. However, the window frame must be deep enough to accommodate the blinds without obstruction. Inside mount blinds are ideal for a minimalist, modern aesthetic.
• Outside Mount: If you prefer to cover the entire window area, including the trim and wall space around the window, an outside mount is the way to go. This type of mount is especially useful for windows that have no frame, are irregularly shaped, or have obstructions like handles or locks that would interfere with inside mounting. Outside mount blinds can make your window appear larger and provide additional light control.

Step 2: Measure the Width

For Inside Mount:

• Measure the width of the window frame at three points: the top, middle, and bottom.
• Use the smallest measurement of these three to ensure the blinds fit inside the window without binding or getting stuck. This ensures a proper fit while allowing for slight variations in window size.

For Outside Mount:

• Measure the width of the area you want to cover, extending the measurement beyond the window frame to achieve full coverage. Ideally, add at least 1.5 to 2 inches on each side to prevent light gaps and create a more finished, tailored appearance.
• For a more dramatic, light-blocking look, you can add a few extra inches to the total width for a more expansive effect. For precision, use a metal tape measure at all times.

Step 3: Measure the Height (or Length)

For Inside Mount:

• Take measurements of the window’s height at the left, center, and right locations. Just like with the width, use the longest measurement to ensure the blinds will fit correctly within the frame.
• If your window has a deep frame or a raised sill, take note of this and adjust your measurements accordingly to prevent any obstruction when the blinds are lowered.

For Outside Mount:

• If you’re going for an outside mount, measure the height from the top of the area where you want the blinds to begin (this is typically above the window frame or trim) down to where you want the blinds to end (usually just below the window).
• Add 2-3 inches of extra height to cover any additional space above or below the window frame, ensuring the blinds have a full and professional look.

Step 4: Consider Obstructions and Clearance

During the measurement process, it’s important to check for any obstructions or irregularities in the window area that might interfere with the blinds. These could include:

• Window handles, locks, or cranks
• Window trim or molding
• Curtain rods or shelves

For inside mount blinds, any obstructions can affect the ability of the blinds to fully function or may prevent them from fitting properly inside the window frame. You may need to adjust your measurements to accommodate these obstacles or opt for different types of blinds (e.g., cordless or top-down-bottom-up).

For outside mount, check if the window trim or hardware will interfere with the installation. Measure beyond the window’s trim to ensure that your blinds will cover any protruding elements.

Step 5: Double-Check Your Measurements

One of the most crucial steps in the process is verifying your measurements. Always measure twice and be sure to double-check your work to avoid mistakes. Here are a few helpful tips to ensure accurate measurements:

• Always use a metal tape measure to avoid stretching or bending that can occur with cloth tapes.
• Despite their apparent similarity in size, measure each window independently. measure each window independently.
• Round your measurements to the nearest 1/8 inch for the most precise results.
• If you’re installing multiple blinds, ensure that each measurement is recorded separately to avoid confusion.

Step 6: Add for Desired Coverage

If you prefer more light control or privacy, you may want to add a few inches to your measurements. This is especially important for outside mount blinds where additional coverage will provide a more finished look and help block out light.

For inside mount blinds, any additional measurements should be minimal. The goal is to make sure your blinds fit snugly inside the window frame without gaps, but not too tight that they become difficult to operate.