Blind Size Calculator
Calculate blind size easily with our free tool. Get practical results, tips, and comparisons for everyday decisions. Includes formulas and worked examples.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
Inside Mount: Blind Size = Window Opening - 1/4 inch
For inside mount blinds, subtract 1/4 inch from both width and height for clearance. For outside mount, add 3 inches (1.5 inches overlap on each side) to both width and height. Check that your window frame depth meets the minimum requirement for your chosen blind type.
Worked Examples
Example 1: Inside Mount Roller Blind
Problem:Your window opening is 36 inches wide by 48 inches tall with a frame depth of 3.5 inches. What size roller blind should you order for inside mount?
Solution:Window width: 36 inches\nWindow height: 48 inches\nDeduct 1/4 inch for clearance from each dimension:\nBlind width: 36 - 0.25 = 35.75 inches\nBlind height: 48 - 0.25 = 47.75 inches\nMinimum depth for roller blind: 1.5 inches\nYour depth: 3.5 inches - sufficient!\nArea: 35.75 x 47.75 / 144 = 11.85 sq ft
Result:Order Size: 35.75' x 47.75' | Depth: OK (3.5' > 1.5' min) | Area: 11.85 sq ft
Example 2: Outside Mount for Multiple Windows
Problem:You have 4 windows each 30 inches wide by 60 inches tall. You want outside mount cellular blinds with 1.5 inch overlap on each side. What is the total coverage area and estimated cost?
Solution:Individual blind width: 30 + 3 = 33 inches\nIndividual blind height: 60 + 3 = 63 inches\nIndividual area: 33 x 63 / 144 = 14.44 sq ft\nTotal area for 4 blinds: 14.44 x 4 = 57.75 sq ft\nCellular blind estimate: ~$12/sq ft\nEstimated cost: 14.44 x $12 = $173 each, $692 total
Result:Each Blind: 33' x 63' | Total Area: 57.75 sq ft | Est. Cost: $692 for 4 blinds
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy