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Film Roll Length Calculator

Estimate wound film length from roll outside diameter, core outside diameter, and film thickness, all in inches. Formula: length = π × (roll OD² − core OD²) ÷ (4 × film thickness). Assumes a tightly wound roll with uniform effective thickness and no air-gap correction.

Example values are prefilled to demonstrate the calculation. Replace them with values for your product, package, equipment, and operating conditions.

Inputs

Roll dimensions and film gauge

Range: at least 0.0001 in

Enter the measured wound roll's outside diameter in inches.

Range: at least 0.0001 in

Enter the outside diameter of the empty core in inches; it must be smaller than roll outside diameter.

Range: at least 0.0 mil

Enter effective total film gauge in mil. 1 mil = 0.001 inch; for multilayer film use the total effective caliper, not one layer only.

Result

Valid
Film annular cross-section area (in²)
106.029 in²
Effective gauge converted to inches (in)
0.002000 in
Estimated film length (ft)
4,417.9 ft
Estimated film length (in)
53,014.4 in

Calculation

Film annular cross-section area (in²)
—
Effective gauge converted to inches (in)
—
Estimated film length (in)
—
Estimated film length (ft)
—

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