Getting the measurements right is the single most important step when ordering custom blinds. A blind that's even 1/4" too wide won't fit inside the frame — and one that's too narrow will let light bleed in around the edges. Follow this guide and you'll get a perfect fit every time.
Step 1: Decide on Inside Mount or Outside Mount
Before you measure anything, decide how you want to hang your blinds. This changes what you measure.
- Inside mount — The blind hangs inside the window frame, flush with the wall. Gives a clean, built-in look. Requires at least 1.5" of window depth to mount the brackets.
- Outside mount — The blind hangs on the wall above and around the frame. Ideal for shallow windows, or when you want to block more light or make a small window appear larger.
How to Measure for Inside Mount Blinds
Width
- Measure the inside width of the window opening at three points: top, middle, and bottom.
- Use the narrowest of the three measurements.
- Record to the nearest 1/8".
- Do not deduct anything. AiryBlinds automatically deducts 3/8" during production for a proper inside-mount fit.
Height
- Measure from the top of the window opening to the windowsill at three points: left, center, and right.
- Use the shortest measurement.
- Record to the nearest 1/8".
⚠️ Common mistake: Many people deduct 1/2" from their width "just to be safe." Don't — we handle the deduction. If you deduct, your blind will be too narrow.
How to Measure for Outside Mount Blinds
Width
- Decide how far beyond the window frame you want the blind to extend on each side (typically 1.5"–3" per side to minimize light gaps).
- Measure the total width you want the blind to cover — frame edge to frame edge, plus your overlap on both sides.
- Order that exact measurement. No deduction is applied for outside mount.
Height
- Decide how high above the frame you want to mount the brackets (typically 2"–4" above the frame).
- Measure from your chosen mount point down to where you want the blind to end (usually the sill, or 0.5" below it).
- Order that exact measurement.
Tools You'll Need
- A metal measuring tape (not a fabric tape — fabric stretches)
- A pencil and notepad, or your phone for notes
- A helper for very wide or tall windows
What If My Windows Are Different Sizes?
Measure each window individually. Even windows that look the same size are often slightly different due to how the home was built. Add each blind to your cart separately with its own dimensions.
Minimum and Maximum Sizes
AiryBlinds custom blinds are available in a wide range of sizes. If your window falls outside standard sizing ranges, contact us before ordering and we'll confirm whether we can accommodate your dimensions.
Double-Check Before You Order
Measure twice, order once — custom-sized blinds are made to your exact specifications and cannot be returned or exchanged for sizing errors. When in doubt, measure a third time.
Ready to order? Browse our faux wood blinds or contact us if you have any questions about your measurements.