Getting the perfect fit for your new blinds comes down to two simple things: a good tape measure and a little know-how. Forget the guesswork—we’ll walk you through how to measure for blinds with total confidence, ensuring a flawless, professional-looking result. This guide covers the exact steps for both inside and outside mount blinds, so let's get you ready to order.

Table of Contents

• Before You Start: Inside Mount vs. Outside Mount
• How to Measure for Inside Mount Blinds
• How to Measure for Outside Mount Blinds
• Common Measuring Mistakes to Avoid
• The Only Tools You'll Need
• Frequently Asked Questions

Before You Start: Inside Mount vs. Outside Mount

Before you pull out that tape measure, you need to make one critical decision: will your blinds be an inside mount or an outside mount? This choice dictates every measurement you'll take and defines the final look.

• Inside Mount: Blinds fit snugly inside the window frame, creating a clean, built-in look that showcases your window trim. This is the most common and popular choice for a minimalist aesthetic.
• Outside Mount: Blinds are installed on the wall or trim above the window, completely covering the opening. This is a great solution for hiding imperfect trim, blocking more light, or when a window frame is too shallow for an inside mount.

Inside vs. Outside Mount: A Quick Comparison

This table breaks down the key differences to help you choose the right style for your home.

While measuring for blinds and curtains share some similarities, the process for curtains involves different considerations around rod placement and fabric drape. We dive deeper into these techniques in our guide on how to measure a window for curtains perfectly. Understanding general size measurement principles is also a huge help for all sorts of home projects.

How to Measure for Inside Mount Blinds

An inside mount gives you that polished, custom-fit appearance by setting the blinds neatly within the window's frame. To achieve this sleek finish, precision is key. The short answer? Always measure in three places for both width and height.

Step-by-Step Instructions:

1. Measure the Width: Using a steel tape measure, measure the inside width of the window frame at the top, middle, and bottom. Record all three measurements.
2. Identify the Final Width: Circle the narrowest of your three width measurements. This is the number you will use to order your blinds. Using the narrowest dimension ensures the blinds won't scrape or get stuck.
3. Measure the Height: Measure the inside height of the window frame on the left side, in the center, and on the right side. Record all three.
4. Identify the Final Height: Circle the longest of your three height measurements. This ensures your blinds will be long enough to cover the entire window pane.
5. Measure the Depth: Finally, measure the depth of your window frame, from the glass to the edge of the trim. This ensures there is enough space for the headrail to be mounted.

Why is measuring in three spots so important? Because windows are almost never perfectly square. Years of a house settling can cause frames to bow slightly. This three-step check is our expert trick for catching those imperfections and guaranteeing a perfect fit.

Crucial Tip: Always provide the exact window opening measurements to your supplier. Never round up or down, and do not make any deductions yourself. The manufacturer will automatically make the small, necessary adjustments (usually 1/4" to 1/2") to ensure the blinds fit and operate smoothly inside the frame.

Choosing the right blind style is just as important as the measurement. Explore our collection of blinds to find the perfect match for your home's aesthetic.

How to Measure for Outside Mount Blinds

Outside mount blinds are a fantastic solution for making a window appear larger, hiding unattractive trim, or achieving maximum light blockage. The key to this style is the "overlap"—the amount the blind extends beyond the window opening.

Step-by-Step Instructions:

1. Determine Your Overlap: Decide how much you want the blinds to overlap the window frame. For optimal light control and privacy, we recommend adding 1.5 to 3 inches to each side (width) and to the top and bottom (height). For blackout needs in a bedroom, you can go as wide as 6 inches on each side.
2. Measure the Width: Measure the width of your window opening, including any trim you wish to cover. Then, add your desired overlap to this measurement. (e.g., 35" window + 3" overlap on each side = 41" final blind width).
3. Measure the Height: Decide where you will mount the headrail, typically 2 to 3 inches above the window frame. Measure from that point down to where you want the blinds to end (usually the bottom of the windowsill). This is your final height measurement.
4. Check for Obstructions: Before finalizing your numbers, look for anything that might get in the way, such as doorknobs, light switches, or window cranks. Ensure your chosen overlap provides enough clearance for the blinds to operate freely.

The right measurements are the foundation of a great window treatment strategy, a topic we explore in our guide on how to choose window treatments.

Common Measuring Mistakes to Avoid

A tiny measuring mistake can lead to a big headache. I've seen even experienced DIYers fall into a few common traps. Knowing what to watch for is half the battle.

• Measuring Old Blinds: Never measure your old blinds instead of the window. Your old blinds may have been sized incorrectly or warped over time. Always measure the window opening itself.
• Using the Wrong Tape Measure: A fabric or vinyl sewing tape can stretch, leading to inaccurate numbers. A rigid steel tape measure is the only tool that guarantees precision.
• Forgetting Obstructions: Window cranks, locks, and even nearby light switches can interfere with blind operation. Always check for clearance before you order.
• Mixing Up Width and Height: It's a simple slip-up, but it happens! Always write your measurements down as Width x Height (W x H) and double-check before placing your order.

The global window blinds market is projected to grow significantly, reaching over $3.5 billion by 2030, according to a market analysis by Global Growth Insights. This growth is driven by consumer demand for custom, perfectly-fitted solutions, making accurate measurements more important than ever.

The Only Tools You'll Need

You don't need a massive toolbox for this job. Being prepared with a few key items makes the process smooth and accurate.

• Steel Tape Measure: This is non-negotiable for accuracy.
• Pencil and Paper: To write down measurements immediately.
• Sturdy Step Ladder: To safely reach the top of taller windows.

Having these essential installation tools ready to go prevents interruptions and helps ensure you get reliable numbers in one go.

Frequently Asked Questions

What if my window isn't perfectly square?

This is extremely common. That's precisely why we recommend measuring the width and height in three different places. For an inside mount, you will use the narrowest width and the longest height. This ensures the blind fits within the tightest part of the frame and is long enough to cover the entire opening.

Should I make deductions for an inside mount?

No, never make your own deductions. Provide the exact, precise measurement of the window opening to the manufacturer. They are the experts and will automatically deduct the correct amount (typically 1/4" to 1/2" from the width) to ensure the headrail fits and the blinds operate smoothly without scraping the frame.

How do I measure for bay or corner windows?

Bay and corner windows require careful planning. Treat each section of a bay window as a separate window, but pay close attention to how the headrails will meet at the angles. For corner windows, you must account for the depth of the headrails to prevent them from interfering with each other. We recommend consulting the manufacturer's specific guides for these complex applications.

Can I just measure my old blinds?

We strongly advise against this. It’s a common shortcut that often leads to a poor fit. The original blinds may have been measured incorrectly, or they may have warped over time. The only way to guarantee a perfect fit for your new blinds is to measure the window frame itself. A proper fit is also a key part of window safety, which we cover in our guide on how to childproof windows.

Ready to put your new measuring skills to the test? At Joey'z Shopping, we have a wide selection of beautiful, high-quality blinds to complete any room in your home.

Shop Our Full Collection of Blinds Now