How to Measure for Window Shades and Blinds: A Simple Step-by-Step Guide from Metro Shutters, Shades & Blinds of Tulsa.

Measuring windows sounds simple, but getting it right is what separates a clean, custom fit from gaps, light leaks, and costly remakes.

Over the years, we’ve helped clients all over Tulsa and beyond, including online consultations, vacation homes, and referrals where we walk people through measuring over FaceTime. We realized it would be helpful to create a straightforward guide that explains how to measure correctly without overcomplicating it.

This is the same process we use every day to measure for window shades and blinds. It’s practical, real-world, and designed to help you get accurate results the first time.

Why Proper Window Measurements Matter

Window treatments do more than look good. They control light, add privacy, and finish a space. But none of that works if the measurements are off.

A good measurement means:

• clean lines with minimal gaps

• smooth operation

• proper light control

• fewer remakes or adjustments

Small differences matter more than most people realize. Walls aren’t perfectly flat, trim isn’t always square, and tiny variations can change how a shade sits once installed.

Blinds vs. Shades: Know What You’re Measuring For

Before measuring, it helps to know what you’re ordering.

Blinds

• Have slats that tilt open or closed

• Common in faux wood, wood, or aluminum

Shades

• Made from fabric or woven materials

• Roll, fold, or stack depending on style

• Includes roller shades, cellular shades, Roman shades, and woven woods

Each style sits slightly differently in a window, which is why accurate measuring matters., it’s helpful to know the difference between blinds and shades:

1. Blinds have slats you can tilt open or closed. They come in wood, faux wood, aluminum, and vinyl.

2. Shades are made from fabric and roll or fold up. Popular types include roller, cellular, roman, and pleated shades.

Each style covers the window in a different way, which can change how you measure. But don’t worry, we’ll show you how to do both.

How to Measure for Window Shades and Blinds Correctly

Before you measure anything, decide what you’re ordering and how it’s going to mount. That single decision changes everything. A shade measured for an inside mount cannot be measured the same way as an outside mount, and that is where most DIY orders go sideways.

Here’s the simple rule we follow when we walk a client through measurements remotely:

• Inside mount: measure the opening

• Outside mount: measure the coverage

What you’ll need:

• A steel tape measure (not a cloth one)

• A pencil and paper (or notes app)

• A step stool if needed

• A second set of hands for wide windows

For every window, take three measurements for width (top, middle, bottom) and three for height (left, center, right). Write them down immediately and label each window or room clearly. Do not round up. Go to the nearest 1/8 inch.

Now you’re ready to choose the mount type and measure the right way.

You’ll need this when you order your custom window coverings from Metro Shutters, Shades, and Blinds. If you'd like to learn how to use a measuring tape properly, check out this step-by-step guide from a trusted source.

Inside Mount vs. Outside Mount

Inside Mount

• Fits inside the window frame

• Clean, built-in look

• Requires accurate measurements and enough depth

Outside Mount

• Mounted outside the frame

• Great for shallow windows or light control

• Makes windows appear larger

There isn’t a right or wrong choice. It depends on the window and the look you want.

How to Measure a Window for Blinds (Step-by-Step)

Blinds need a tighter, more exact fit because there’s no fabric flexibility. This is why the smallest measurement matters.

Inside Mount Blinds

1. Measure the width in three places: top, middle, and bottom.

2. Always use the smallest width measurement.

Example: if the top is 35”, middle is 34 7/8”, and bottom is 34 3/4”, you order using 34 3/4”.

3. Measure height in three places: left, center, and right.

4. Use the tallest height measurement.

5. Measure to the nearest 1/8 inch and write everything down clearly.

Reason: walls and trim are rarely perfectly square. Using the smallest width prevents blinds from binding or scraping the sides.

Outside Mount Blinds

In Tulsa, Oklahoma, many homes have shallow or uneven window frames. For these, an outside mount can be a better choice. Here’s how to do it:Decide how much coverage you want beyond the window opening. In most cases, I add about an inch to each side for an outside mount, depending on the window and the overall look we’re going for. Too much extra width can make a custom shade look oversized or like it wasn’t truly made for the space, which takes away from that clean, custom-fitted finish.

It’s a small detail, but proper outside mount sizing is what separates a clean, designer-level install from something that just looks off once it’s up.

Add enough width and height to visually frame the window.

How to Measure a Window for Shades (Step-by-Step)

Shades measure a little differently because fabric naturally allows a small light gap, especially with roller shades.

For roller shades, that light gap is normal and expected. Because of that, measurements don’t have to be treated exactly the same as blinds.

However, if you are measuring for honeycomb shades, woven woods, or Roman shades, you want to follow the same measuring method used for blinds. These products fit tighter in the opening, so accuracy matters the same way it does with blinds.

Inside Mount Shades

1. Measure width in three places: top, middle, and bottom.

2. For roller shades, measuring the top width is typically sufficient since roller shades naturally allow a light gap due to how the fabric sits on the roll or inside the cassette. In some situations, additional checks may be needed depending on the window details, which is why professional measuring is always recommended when possible.

3. For honeycomb, woven wood, and Roman shades, use the smallest width measurement, just like blinds.

4. Measure height in three places and use the tallest height.

5. Record measurements to the nearest 1/8 inch.

Outside Mount Shades

In Tulsa, Oklahoma, many homes have shallow or uneven window frames. For these, an outside mount can be a better choice.

1. Decide how much coverage you want beyond the window opening.

2. For most roller shades, adding about an inch to an inch and a half per per side creates a clean, balanced look.

3. Measure total width and height based on your desired finished coverage.

Inside mount shades measured and installed by Metro Shutters, Shades and Blinds of Tulsa.

Outside mount shades. Cassette was measured within the inner trim line at the clients request. This gives a framed, built-in look when the shades are raised.

Final Reminder Before You Measure

If you’re feeling a little nervous about measuring, that’s normal. Even people who have done it before double-check themselves.

Just remember:

• Slow down and measure carefully

• Write everything down clearly

• Measure every window individually, even if they look the same

• When in doubt, measure again

Small details make a big difference in how custom shades and blinds look once installed. Taking an extra minute now saves headaches later.

And if you’d rather have a second set of eyes, that’s what we’re here for. We do virtual measuring walkthroughs all the time and are happy to help you get it right the first time.

• Blinds or shades

Final Measuring Tips from Metro Shutters, Shades, and Blinds

• Measure twice before ordering

• Record everything clearly by room

• If you’re unsure, start with one window first

• Don’t guess. Write it down as you go

• When in doubt, ask a professional before placing the order

Measuring gets easier quickly once you do the first one or two windows. The goal is clean lines, proper fit, and a finished look that feels intentional, not forced.

Measuring might seem tricky at first, but once you do one or two windows, the rest will feel much easier.

Need help getting the perfect fit? Contact Metro Shutters Shades and Blinds for expert measuring support and custom-fit solutions that match your space. We’re here to make it easy and get it right the first time.