What’s the Difference Between Inside vs. Outside Mount Blinds?

Window treatments do more than “finish” a room. They help you control light for better sleep, add privacy, reduce glare, and make your space feel more comfortable—without turning your home into a project (or a weekend you’ll regret).

One of the most common (and most important) decisions DIY shoppers ask about is this:

Should I choose an inside mount or an outside mount?

After 60+ years of combined window-treatment experience, we’ve learned there’s no single “best” option—just the right choice for your window depth, trim, and goals. Here’s a clear, no-pressure breakdown (with fewer headaches later).

Quick answer: inside mount vs. outside mount

Inside mount blinds = the blind/shade sits inside the window frame for a clean, built-in look.

Outside mount blinds = the blind/shade mounts above or on the window trim/wall and overlaps the opening.

If you’re not sure which you have (or what your window can handle), don’t worry—this is exactly the kind of question our team helps with every day. And yes, we’d rather answer it now than have you “make it work” later.

Inside mount blinds: clean look, precise fit

Inside mount (also known as IM or IB for inside brackets) is popular because it looks tailored and modern. The window trim stays visible, and the treatment feels like it belongs to the window.

Best for

A clean, streamlined look
Windows with enough depth (so the headrail doesn’t stick out too far)
Homeowners who want the trim to remain a design feature

What to watch for

Depth matters. If your window frame is shallow, an inside mount may not fit—or it may protrude more than you want.
Measuring needs to be accurate. There’s very little room for error.

With decades in the industry, we can tell you this is where most DIY frustration happens: people love the inside-mount look, but the window simply doesn’t have the depth to support it. A quick depth check up front saves a lot of hassle (and a spicy vocabulary) later.

Helpful tip

Before you order inside mount blinds, measure the inside depth of the window frame and compare it to the product’s minimum depth requirement. Also, use the measuring guide specific to your product type (for example, aluminum mini blinds). The right guide will tell you exactly where to measure and how to handle small variations.

Outside mount blinds: flexible fit and better light coverage

Outside mount blinds (also known as OM or OB for outside brackets) are installed outside the window frame—typically above the window opening, on the trim, or on the wall. This is a great option when the window frame is shallow, uneven, or just not cooperating.

Best for

Shallow window frames (common in older homes and some apartments)
French doors and other tricky applications
Covering less-attractive trim without replacing it
Reducing light gaps by overlapping the opening
Uneven/ out-of-square window opening

Why many DIYers choose it

Outside mount gives you more flexibility. You can mount higher and wider than the window opening, which can:

Improve privacy
Block more light (especially on the sides)
Make a small window look larger

From our experience, outside mount is also a smart “problem-solver” when windows aren’t perfectly square—something we see all the time in real homes (because real homes are not showroom-perfect, no matter what Instagram says).

Which one should you choose? (A simple decision guide)

Choose inside mount blinds if you want:

A built-in, polished look
Your window trim to stay visible
A fit that works with your window depth

Choose outside mount blinds if you need:

A solution for shallow frames
Better light control (less edge light)
Coverage that hides imperfect trim or older frames

Common questions we hear (and quick answers)

“Will outside mount look bulky?”

Not necessarily. With the right style and placement, outside mount can look clean and intentional—especially if you mount it slightly higher and wider for a balanced look.

“Which mount blocks more light?”

In most cases, outside mount blinds can reduce light gaps more because they overlap the window opening.

“What if I’m not sure my window is deep enough?”

That’s normal. Measure the depth inside the frame and compare it to the product’s minimum depth requirement.

And don’t guess—each product on Blindsonline.com has its own measuring guide, so you’ll know exactly where to measure, what depth you need, and how to handle small variations. If you’re still stuck, ask—we’ve helped thousands of DIYers make this call before they click “order.”

Ordering at Blindsonline.com

We carry both inside mount blinds and outside mount blinds across many blind and shade styles. When you select a product and start customizing, you’ll be able to choose your mount type and enter your measurements.

If you want a second set of eyes before you order, reach out. With 60+ years of combined experience, we’re here to help you get a result that looks good, fits right, and feels like a smart purchase—without pressure.

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