How to Size 2-Inch Blinds for Your Windows? | Measure Once, Right

To size 2-inch blinds, measure the window opening’s width at the top, middle, and bottom and use the narrowest number, then check the frame depth against the blind’s minimum requirement before ordering.

Most blinds that get returned were never the wrong color or style — they were ordered off a single width measurement taken at eye level. A window opening that looks square is often a quarter inch wider at the top than the bottom on older homes, and one steel tape measure run at three heights catches that before it costs you a restocking fee. Whether your blinds sit inside the window recess or hang on the wall above it decides what you measure, so pin that down first.

Inside Mount vs. Outside Mount: Which One Are You Measuring For?

Inside mount blinds fit within the window frame recess and leave the trim visible; outside mount blinds hang on the wall or trim above the opening and cover more of the wall. The choice changes every measurement you take afterward.

Inside mount is the cleaner look and works well when your window has enough recess depth for the headrail and brackets. It also leaves less room for error — the blind has to physically fit in that opening, and depth decides whether it can.

Outside mount is the practical pick when the frame is shallow, when you’re covering a window with obstructions, or when you want better light blocking. You gain coverage and forgiveness on width, and you lose the flush look.

Whichever direction you go, record every number to the nearest 1/8 inch with a steel tape. Cloth tapes stretch and sag, and Home Depot’s measurement guidance calls for metal for exactly that reason.

How Do You Measure a Window for Inside Mount Blinds?

For an inside mount, measure the width of the opening at the top, middle, and bottom, then order using the smallest of those three numbers. Measure the height at the left, middle, and right of the opening.

1. Run a steel tape horizontally across the top of the opening, then the middle, then the bottom. Write down each width.
2. Run the tape vertically down the left side, the middle, and the right side. Write down each height.
3. Use the narrowest width for your order. Using the widest guarantees the blind will not drop into the opening.
4. Measure the depth of the recess from the front of the frame back to the glass or the deepest obstruction.
5. Check whether you have flat mounting surface above the opening for the headrail and brackets.

Height handling is where retailers diverge, and it matters. Some blind guides use the shortest of the three height readings for recess-fit products, while some manufacturers publish their own ordering rule that overrides that. Read the specific product’s measuring instructions before you commit to a number — the difference is usually small, but a half inch of gap shows at the sill.

Depth is the quiet dealbreaker. Measure your actual recess and match it to the product’s spec sheet, not to a general rule.

What Do You Measure for Outside Mount 2-Inch Blinds?

For an outside mount, measure the full area you want the blind to cover rather than the window opening, and confirm you have at least 2 inches of flat surface above the opening for the headrail and brackets.

Start at the outer edge of where you want coverage on the left and run across to the same point on the right. Then measure from the top of your intended coverage down to the bottom. Add overlap beyond the window frame on all sides if you’re chasing light control — more overlap blocks more light, and the exact allowance varies by retailer, so check the product page.

That 2-inch flat-surface requirement is non-negotiable for outside mount. Trim, crown molding, or a window that sits close to the ceiling can leave you nowhere to anchor the brackets, and no amount of careful measuring fixes that afterward.

Before ordering, walk the whole opening and look for anything that will get in the way: molding, radiators, deadbolts, curtain hardware, or a crank handle. Blinds.com’s measuring guide and Lowe’s window-measuring guide both treat obstruction checks as part of the job, and it’s the step people skip.

One more accuracy habit worth building: write down width first, then height, every single time, and never eyeball a number you intend to type into an order form. Mixing up width and height is common enough that Home Depot’s guide flags it directly, and it’s the mistake that turns a perfect measurement into a wrong-sized blind.

If you’ve measured and you’re ready to pick a product, our roundup of the best 2-inch blinds for windows narrows down what fits standard recesses and shallow frames. For the official measurement procedures behind these numbers, Home Depot’s how to measure for blinds and shades guide walks through the process step by step.

Frequently Asked Questions

Should I round my blind width up or down?

Round width down to the nearest 1/8 inch for inside mount blinds. An opening that measures 34 5/8 inches gets ordered as 34 5/8 inches, never pushed up to 34 3/4. Going larger means the blind won’t seat in the recess, while a hair narrow still fits and is hidden by the mounting hardware on most products.

What’s the minimum window depth for 2-inch blinds?

It depends on the blind.

Do I measure the window glass or the frame opening?

For inside mount, measure the frame opening itself — the recess between the jambs, top to bottom and side to side — not the glass. For outside mount, measure the area you want covered, which extends past the frame on every side you want shaded. The glass measurement is never the ordering number.