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.
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
Frequently Asked Questions
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
What formula does Blind Size Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.
Is Blind Size Calculator free to use?
Yes, completely free with no sign-up required. All calculators on NovaCalculator are free to use without registration, subscription, or payment.
Can I share or bookmark my calculation?
You can bookmark the calculator page in your browser. Many calculators also display a shareable result summary you can copy. The page URL stays the same so returning to it will bring you back to the same tool.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.
Does Blind Size Calculator work offline?
Once the page is loaded, the calculation logic runs entirely in your browser. If you have already opened the page, most calculators will continue to work even if your internet connection is lost, since no server requests are needed for computation.