๐Ÿ“Œ Key Takeaway: Inside-mount and outside-mount blinds require different measurement approaches โ€” getting this wrong is one of the most common reasons custom blinds don't fit properly on arrival.

Inside Mount vs. Outside Mount

  • Inside mount โ€” blinds fit within the window frame itself, requiring at least 1.5-2 inches of depth for proper mounting hardware clearance.
  • Outside mount โ€” blinds mount on the wall or trim surrounding the window, covering the full frame โ€” a good option when frame depth is insufficient for inside mount, or when you want to make a window appear larger.

Basic Measuring Steps

  • Measure width at the top, middle, and bottom of the window opening โ€” use the narrowest measurement for inside mount to ensure clearance.
  • Measure height at the left, center, and right sides โ€” use the longest measurement for inside mount.
  • Measure frame depth to confirm inside-mount feasibility before ordering.
  • For outside mount, decide how far beyond the frame you want the blinds to extend on each side (typically 2-3 inches) and add that to your frame measurements.

Why Professional Measuring Is Often Free

Many retailers offer free professional measuring even if you plan to self-install the blinds afterward โ€” worth taking advantage of specifically to avoid an expensive custom-order mistake, since custom blinds typically aren't returnable once cut to size.

Tools You'll Need

A steel tape measure (not cloth, which can stretch and introduce error) is essential for accurate results โ€” measure to the nearest eighth of an inch for custom orders, since small errors compound when applied to multiple windows across a whole-home project.

Frequently Asked Questions

What happens if I measure incorrectly for custom blinds?

Custom-cut blinds typically can't be returned or exchanged once manufactured to your specific measurements โ€” this is exactly why free professional measuring services are worth using, even for a DIY installation.

Do I need different measurements for each window, even if they look the same size?

Yes โ€” even windows that appear identical often have slight variations due to home settling or construction tolerances. Measure each window individually rather than assuming they're all the same.

๐Ÿ”Ž How we research: The ServiCover Editorial Team compiles prices and guidance from published 2026 cost guides, manufacturer information and industry sources. Prices are national ranges and vary by location, home and provider, so always compare written quotes. We don't perform the work ourselves, and we may earn a commission when you request quotes through our partners โ€” see our Advertiser Disclosure.