Skip to content
BLINDSPEC

Signature tool · measure-first

Measure & Fit Checker

Custom blinds are made to size and generally not returnable, so the fit question is worth two minutes before your money is on it. Enter your window and get the typical deduction rule for your mount and product, the minimum depth to confirm, and a printable measure checklist.

Your window

Inside mount — the factory deducts the width

Report the exact opening width and height you measured. Most sellers subtract a typical 1/4"–1/2" so the blind clears the frame (a few ask you to deduct instead — confirm which). That deduction is why an inside mount always leaves a small light gap at the edges.

Minimum depth for cellular / honeycomb

Typical minimum inside-mount depth is about 3/4" — Slim stack — inside-mounts in shallow frames; deeper (about 2"+) to sit fully recessed. Measure your shallowest depth against the seller’s stated minimum and flush figures; if the frame is too shallow, switch to an outside mount.

Typical ranges — confirm with the seller

Before you order

Every seller applies its own deductions — confirm against your seller's measuring guide before ordering. Custom blinds are made-to-size and generally not returnable.

Measure-once checklist
  1. Use a steel tape measure, not a cloth one, and measure the bare opening — do not deduct anything yourself unless the seller’s guide says to.
  2. Width: measure at the top, middle, and bottom of the opening; record the narrowest of the three.
  3. Height: measure at the left, center, and right; record the longest (or per the seller’s rule).
  4. Depth: measure the flat, unobstructed depth to the glass or nearest hardware (cranks, handles, sensors) at the shallowest point.
  5. Note anything in the way — cranks, alarm sensors, deep trim — that a blind must clear.
  6. For an outside mount, decide overlap: about 2–3" beyond the opening on each side and above.
  7. Confirm who applies the deduction (you or the factory) in the seller’s measuring guide before you submit.
  8. Double-check the numbers, then order — custom blinds are generally not returnable for a mismeasure.

Measuring & Installation guides

Inside vs outside mount, the deductions to confirm, and drill-free options that hold.

The measuring hub

Everything on getting the numbers right — glossary terms, comparisons, and the checklist.

Printable measure checklist

The measure-once worksheet to print and take to the window before you order.