In
Inside mount
Shade sits inside the window frame for a clean, built-in look. Requires enough frame depth (check your Amazon listing). Best when the frame is square and unobstructed.
How to measure
Accurate measurements are the difference between a perfect fit and a return. Use a metal tape measure, record to the nearest 1/8 inch, and double-check every number before you order on Amazon.
What you need
- Metal tape measure (not cloth)
- Notepad or phone notes app
- Step stool if needed for tall windows
- Helper for wide windows (optional)
Step 1
Choose inside mount or outside mount
Out
Outside mount
Shade mounts on the wall or trim above/around the opening. Hides imperfect frames, reduces light gaps, and works when depth is limited. Order wider and taller than the opening.
Tip
Rule of thumb
Inside mount = clean inset look (needs depth). Outside mount = more coverage and fewer light gaps.
A
How to measure for inside mount
- Width: measure the inside width at the top, middle, and bottom. Use the narrowest width.
- Height: measure the inside height at the left, center, and right. Use the longest height if you want full coverage to the sill.
- Depth: measure how deep the frame is. Confirm the minimum depth listed on the Amazon product page.
- Order the exact opening size only if the listing says it will factory-deduct for clearance. Otherwise follow the listing’s inside-mount rules carefully.
B
How to measure for outside mount
- Decide the coverage area first — typically 2–4 inches wider than the opening (1–2 inches per side) for better light control.
- Width: measure the total width you want the shade to cover (opening + overlap on both sides).
- Height: measure from the intended top mount point down to where you want the shade to end (sill, apron, or below for more privacy).
- Make sure there is a flat mounting surface and no handles, alarms, or trim that will block the headrail.
Pro tips before you order
- Always use a metal tape measure and write numbers as you go.
- Measure twice. Order once.
- Windows are rarely perfectly square — that is why we take three width and three height readings.
- For no-drill / tension shades, confirm the window opening range (min–max width/height) on Amazon.
- For cordless cellular and zebra styles, leave room for the bottom rail so the shade hangs level.
- If between sizes, read the listing notes. Many custom shades are made to your entered size and cannot be returned if the measurement was wrong.
- Take a photo of your notes. It helps if you order multiple windows.
Product notes
Notes by product type
| Style | Measuring notes |
|---|---|
| Cellular / honeycomb | great for inside mount when depth allows; check cell size and headrail depth on the listing. |
| Zebra (day/night) | dual-layer fabric needs clean vertical travel — measure carefully for plumb frames. |
| Top-down bottom-up | confirm you have clearance for both top and bottom rail operation. |
| Roller | simple raise/lower; outside mount is common when frames are shallow. |
| No-drill tension | fit depends on exact opening size and surface friction — follow the Amazon size chart exactly. |
Ready to shop with confidence?
Once your width, height, and mount type are confirmed, browse Flamax styles and complete size selection on Amazon.