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Packaging Web Roll Yield and Runtime Calculator

Estimate wound web length, usable length after user-entered loss, whole repeats, package yield, and machine runtime from roll geometry. Formula: web inches = π × (roll OD² − core OD²) ÷ (4 × effective caliper); usable web = web length × (1 − loss fraction); repeats = floor(usable web ÷ repeat pitch); packages = repeats × lanes. Mils are converted using 1 mil = 0.001 in. The roll formula is a geometric estimate for a uniformly thick, tightly wound roll, not a normative packaging-machinery formula. ASTM D6988-26 is a guide for plastic film test-specimen thickness; its stated scope excludes commercial product classification and QC thickness measurement. Use material/specification-supported effective caliper, not an assumption that the standard certifies wound-roll caliper. References: NIST mil definition https://www.nist.gov/glossary-term/40906; ASTM D6988-26 https://store.astm.org/d6988-26.html; representative calculator example https://packaging.webtech360.com/tools/roll-length-calculator/.

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

Inputs

Roll and machine dimensions

Range: at least 0 in

Measure the wound roll outside diameter in inches, across the outside of the wound web. If the roll is oval, use a representative average of perpendicular readings.

Range: at least 0 in

Measure the core outside diameter in inches at the surface where the web is wound. Do not enter the core's inside diameter.

Range: at least 0 mils

Enter effective total web caliper in mils (1 mil = 0.001 inch). For laminates, use total effective caliper supported by supplier/specification or a suitable measurement. ASTM D6988-26 addresses test-specimen thickness and is not a commercial-roll QC method.

Range: at least 0 in/repeat

Enter the actual machine repeat/cut pitch in inches: one longitudinal advance that produces one package per lane.

Range: at least 0 count/repeat

Enter the whole number of finished packages made across the web per repeat.

Range: 0–1 0–1

Enter the share of theoretical web length treated as unusable, such as 0.02 for 2%. This is a planning allowance, not a standard loss rate; The prefilled value is illustrative only, not a site measurement or industry benchmark; replace it with data for the selected scope.

Range: at least 0 packages/min

Enter representative sustained good finished packages per minute, including all lanes. Do not enter cycles/minute unless converted to all-lane package output. A positive rate is required for runtime; The prefilled value is illustrative only, not a site measurement or industry benchmark; replace it with data for the selected scope.

Result

Valid
Valid
Estimated whole packages per roll (count)
10,390 packages
Estimated roll runtime (hours)
2.89 h
Estimated roll runtime (min)
173.2 min
Estimated usable web after loss (ft)
2,164.75 ft
Estimated usable web after loss (in)
25,977.0 in
Estimated web length before loss (ft)
2,208.93 ft
Estimated web length before loss (in)
26,507.2 in
Whole machine repeats per roll (count)
5,195 repeats
Estimate limitations
Roll length assumes uniform effective caliper and tight winding. Air gaps, compression/tension, telescoping, liners, ovality, edge trim, and actual splice/setup loss can change realized footage and yield. Validate estimates against supplier footage or a measured unwind.

Calculation

Estimated web length before loss (in)
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Estimated whole packages per roll (count)
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