What does this tool do?
Film is sold by the square foot or in fixed-width rolls, so the glass area plus a trimming allowance sets the order. This calculator totals the glass area, adds waste and turns it into a supply cost.
The Formula
Glass area = windows × width × height ÷ 144; order area = glass area × (1 + waste %)Frequently Asked Questions
How much waste should I allow?
Five to ten percent covers trimming and mistakes on simple rectangles. Add more for arched or divided-light windows where offcuts cannot be reused.
Can I install film myself?
Yes for removable or basic privacy films. Tinted and solar films are usually best installed professionally to avoid bubbles, creases and edge lift.