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Our full measuring guide has an order-size calculator that does the rounding for you, a one-page worksheet (PDF) with room for all three readings, and a 2-minute video.
Tools you need
- Steel tape measure (not fabric — fabric stretches)
- Pencil (to mark bracket positions)
- Notepad or the measurement table below
Inside mount: 3 steps
The blind sits inside the window frame for a clean, built-in look.
Measure width
Measure the inside of the frame at the top, middle, and bottom. Record the narrowest measurement.
Measure height
Measure the inside of the frame on the left, center, and right. Record the longest measurement.
Measure depth
Measure from the front edge of the frame to the glass (or to a crank or lock that sticks out) at three points. Use the smallest.
Measure to the nearest 1/8 inch. If a reading lands on a 1/16 mark, round the width down and the height up. Then enter the exact numbers: don’t take deductions. For inside mounts the factory makes them.
Outside mount: 3 steps
The blind mounts on the wall above and around the window frame. Use this when the frame is too shallow for inside mount, or when you want to block more light.
Measure width
Measure the opening (or the outside of the trim). Add at least 2½" on each side, so at least 5" in total, to block light gaps.
Measure height
Measure from where the headrail will sit, a few inches above the frame, down to where you want the blind to stop. Check the product’s guide for bracket space.
Mark positions
Use a pencil to mark bracket positions on the wall before drilling. Double-check that marks are level.
Check the depth before you choose inside mount
Every blind lists a minimum mounting depth in its product specifications, and it varies from product to product, so there’s no single number that works for all blinds. If your smallest depth reading is less than that product’s minimum, or a crank, latch or lock sticks out into the blind’s path, use outside mount instead.
Look for “minimum mounting depth” or “inside mount depth” in the product’s specifications before you order. Full mounting guide →
5 common measurement mistakes
- Measuring only once. Always measure width and height in three places. Window frames are rarely perfectly square.
- Using a fabric tape measure. Fabric stretches over time. Use a rigid steel tape for accuracy.
- Rounding the wrong way, or deducting. On a 1/16 mark, round the width down and the height up. Enter exact sizes: the factory makes the inside-mount deduction.
- Forgetting frame depth. If you skip the depth check, you may order inside-mount blinds that cannot physically fit inside your frame.
- Measuring the glass, not the frame. For inside mount, measure the frame opening (where the blind sits), not the glass pane itself.
Quick reference: what to order
| Mount Type | Width to Order | Height to Order |
|---|---|---|
| Inside mount | Narrowest of 3 measurements (round down to 1/8") | Longest of 3 measurements (round up to 1/8") |
| Outside mount | Opening or trim width + at least 5" (2½" each side) | Desired coverage, from a few inches above the frame |
| No-drill / tension | Exact inside frame width (shade expands to fit) | Inside frame height |
Your window measurements
Fill in before you shop. Bring this with you to the store or keep it open when ordering online.
| Room | Window # | Width | Height | Depth | Mount Type |
|---|---|---|---|---|---|