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DIY Cost Tools

DIY Cost Tools

Window Film Roll Calculator

Estimate window-film area and whole rolls from pane dimensions, count, trim allowance, and roll size.

Whole number from 1 to 500 panes.
Number from 1 to 240 in.
Number from 1 to 240 in.
Number from 0 to 100 %.
Number from 1 to 240 in.
Number from 1 to 1000 ft.

Enter values in the units shown. Empty fields, fractions, comma-formatted numbers, values outside the listed ranges, and non-finite values are rejected.

Film area
Whole rolls

How to use this calculator

  1. Measure the project or enter costs from a current quote or product label.
  2. Adjust the quantities, coverage, package size, and allowances to match your situation.
  3. Select Calculate, then check the method, worked example, and limitations below.

Formula and method

Area = panes × width × height ÷ 144 × (1 + allowance%). Rolls = area ÷ (roll width ÷ 12 × roll length), rounded up.

Whole packages and pieces are rounded up. Results disappear when an input changes until the new values are calculated.

Worked example

Panes 6 panes; Pane width 28 in; Pane height 48 in; Trim allowance 12 %; Roll width 36 in; Roll length 15 ft. Results: Film area 62.72 sq ft; Whole rolls 2 rolls.

The example uses the values initially displayed in the fields.

Limitations

Area-based roll counts do not account for pane layout, roll direction, offcuts, or manufacturer installation instructions. The film roll must be at least as wide as a pane.

Review and reference

Reviewed October 5, 2026. The default example, input boundaries, arithmetic, rounding, and invalid input behavior were checked. The method is explained on How Our Calculators Work; replace example inputs with measurements or current product specifications. This is a planning estimate.

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