Blinds Inside Mount Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026Why inside mount blinds are never ordered at exact window width
Ordering blinds at the exact frame measurement leaves no room for the headrail and mounting brackets, which can bind against the frame or fail to fit at all - a small clearance gap is subtracted from the measured width before ordering.
Worked example
For a 36-inch wide window opening with 0.75 inches of total clearance:
Mounted Width = 36 - 0.75 = 35.25 in
Frequently asked questions
How much clearance is typical? Most manufacturers build in 0.25 to 0.5 inches of clearance per side (0.5 to 1.0 inches total), though this varies by product line - always check the specific blind manufacturer's recommended clearance before ordering.
What if the frame depth is too shallow? Inside mount requires enough frame depth to hold the mounting brackets and headrail (often 2-2.5 inches minimum) - shallow frames may need an outside mount instead, where the blind is measured to cover the window opening plus overlap on each side.