Before you pick up a tape measure, decide where the shade will hang. Inside or outside the window frame changes the look, how much light gets in at the edges, and how you measure.
What inside mount means
An inside-mount shade sits within the window frame. It gives a clean, built-in look and leaves your trim on display, which is why it’s the most common choice. Because the shade has to fit inside the opening, there’s always a small gap at each side where a thin line of light gets through.
Inside mount also needs a frame that’s deep enough to hold the shade, with nothing in the way. Window cranks, locks, and handles can stop a shade from sitting flush.
What outside mount means
An outside-mount shade hangs on the wall or the trim above the window and covers the whole opening. We recommend overlapping the frame by 2 to 3 inches on each side, or more if you like the look. That overlap is what blocks the light at the edges, so outside mount is the better choice for blackout and privacy.
It also works where inside mount can’t: shallow frames, windows with cranks or locks in the way, and openings that aren’t quite square. Mounted a little higher and wider, an outside-mount shade can even make a window look bigger.
| Feature | Inside mount | Outside mount |
|---|---|---|
| Look | Clean and built-in; shows off the trim | Covers the frame; can make the window look larger |
| Light at the edges | A thin line at each side | Overlap blocks more light |
| Window frame | Needs enough depth, clear of cranks and locks | Works on shallow frames |
| Best for | Light filtering, solar, and Vision | Blackout and privacy |
| What you measure | The exact opening | The finished size you want |
Which one is right for your window?
- Bedrooms and nurseries: outside mount with a blackout fabric gives you the darkest room.
- Living rooms with handsome trim: inside mount keeps the woodwork in view.
- Kitchens and sunrooms: inside mount with light filtering or solar fabric, where a little light at the edges doesn’t matter.
- Shallow frames or cranks in the way: outside mount, so the shade clears whatever is in the opening.
- Small windows you want to look bigger: outside mount, set a little higher and wider than the frame.
You can also add a square or curved cassette to hide the roll for a more tailored look. On a blackout shade, a cassette also helps seal the light at the top.
Picked your mount? Here’s how to measure.
How you measure each one
Use a steel tape and measure every window on its own, even ones that look identical. Write each size down as width by height, to the nearest 1/8 inch.
- Inside mount: measure the width inside the frame at the top, middle, and bottom, and write down the narrowest. Measure the height at the left, center, and right, and write down the longest. Don’t round or subtract anything. Our workroom makes the small deduction so the shade fits inside the frame.
- Outside mount: measure the opening, then add 2 to 3 inches on each side. For the height, measure from where the brackets will go, about 2 to 3 inches above the opening, down to where you want the shade to stop. Make sure there’s a flat spot for the brackets, clear of handles, cranks, and vents. Then enter the exact size you want the shade to be.
And if you’re unsure about a number, call us at (330) 674-2590 before you order. We look over every order before we cut it.
The short answer
Choose inside mount for a clean look when the frame is deep enough and a little light at the edges is fine. Choose outside mount for the darkest room, for shallow or crowded frames, or to make a window look larger. Still on the fence? Call us at (330) 674-2590. If you’re within 100 miles of Millersburg, we can also come measure and install for you.
