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 it’s where most mistakes happen.

Over the years, we’ve helped clients all over Tulsa and beyond, from in-home consultations to walking clients through measurements over FaceTime for vacation homes and referrals. We realized it would be helpful to create a straightforward guide that shows you 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 it right the first time.

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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 details matter more than most people realize. Walls aren’t perfectly flat, trim isn’t always square, and even slight variations can completely change how a shade or blind fits once it’s installed.

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

Blinds

• Have slats that tilt open or closed

• Typically available in faux wood, wood, or aluminum

Shades

• Made from fabric or woven materials

• Roll, fold, or stack depending on the style

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

Each style fits differently, which is why accurate measuring matters.

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How to Measure Window Shades and Blinds Correctly

Before you measure anything, decide what you’re ordering and how it will be mounted. That one decision changes everything.

Inside mounts and outside mounts are measured completely differently, and that’s where most DIY orders go wrong.

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 better light control

• Makes windows appear larger

The right choice depends on the window and the overall look you want.

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What You'll Need to Measure Windows Properly

• 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

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How to Measure Blinds (Step-by-Step)

Here’s the simple rule we use when guiding clients through measurements remotely:

• Inside mount: measure the opening

• Outside mount: measure the coverage

Inside Mount Blinds

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

2. Use the smallest width measurement

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

4. Use the tallest height measurement

5. Record to the nearest 1/8 inch

Walls and trim aren't always perfectly square, which is why we use the smallest width. It keeps blinds from binding or rubbing the sides once installed.

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

Outside Mount Blinds

1. Decide how much coverage you want beyond the opening

2. Add width on each side based on how much coverage you want

3. Measure the height from where you plan to mount above the window down to where you want the blind to end.

4. Add extra height if mounting above the trim for better coverage and a more finished look.

5. Measure to the nearest 1/8 inch

Outside mounts are not restricted by the window opening, which allows for better light control and privacy when sized correctly.

Example: if your window opening is 35”, your finished size will be determined by how much coverage you want beyond the frame.

Proper outside mount measurements help create a cleaner, more intentional finished look once installed.

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How to Measure Shades (Step-by-Step)

Shades measure a little differently than blinds. Because fabric is flexible, small light gaps are normal, especially with roller shades.

For roller shades, a slight gap on the sides is expected.

For honeycomb, woven wood, and Roman shades, measurements are tighter, similar to blinds.

Inside Mount Roller Shades

If your shade is going inside the window frame:

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

2. For roller shades, the top width is typically what we use

3. For other shade types, use the smallest width

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

5. Use the tallest height

6. Record your measurements to the nearest 1/8 inch

Inside mounts create a clean, built-in look but may allow for small light gaps on the sides.

Outside Mount Roller Shades

If your shade is going on the wall or trim outside the window:

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

2. Add about 1 to 1.5 inches on each side for better coverage

3. Measure total width and height based on that coverage

4. For doors, make sure you allow space for handles or hardware

5. If mounting on trim, measure from outer edge to outer edge for the cleanest look

Measuring wider and taller improves coverage, reduces light gaps, and gives a more finished appearance.

Example: If your window is 35 inches wide, your shade may be ordered between 37 and 39 inches depending on coverage preference.

Pro Tip for a Clean Look

If you’re mounting your shade on trim, measure from one outer edge of the trim to the other. This gives you full coverage and a clean, tailored finish.

Final Note

A well-measured shade makes all the difference in how it looks and functions. Taking a few extra minutes now ensures better light control, more privacy, and a finished result that looks intentional.

For most outside mounts, we recommend adding about 1 inch on each side. It gives better coverage without making the shade look oversized or out of place.

It’s a small detail, but proper outside mount sizing is what separates a clean, finished look from something that feels slightly off.

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.

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Final Reminder Before You Measure

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

Just remember:

• Slow down and measure carefully

• Write everything down clearly

• Measure each 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 frustration later.

If you’d rather have a second set of eyes, that’s what we’re here for. We walk clients through measurements all the time and are happy to help you get it right the first time.

Final Measuring Tips for Blinds and Shades

• Measure twice before ordering

• Record everything clearly by room

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

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

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

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

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

If you want to make sure everything is right the first time, we’re here to help. Contact Metro Shutters Shades and Blinds for expert measuring support and custom-fit solutions designed around your space.

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