Should I enter the core's hole diameter?

No. Enter the core's outside diameter where the first web layer touches it. The bore does not represent the material boundary.

Does the thickness include a release liner?

Yes. Include every layer that is wound onto the roll. Omitting a liner overstates the estimated web length.

Why does uptime leave roll length unchanged?

Uptime changes running minutes and planned footage, while the roll's geometry stays fixed. Compare roll equivalents to see how the production plan changes.

Does this estimate accepted production footage?

No. Planned running footage excludes downtime but includes any material later rejected. Apply separately measured quality losses when planning accepted output.

Industrial Packaging Materials Manufacturing calculator

Roll Diameter Capacity Calculator

Estimate web length from roll diameter, core diameter and full material thickness. Add line speed, scheduled minutes and expected uptime to compare that capacity with your production window.

What this calculator does

Estimate the web length held by a measured roll and compare it with planned running footage.

Formula used

Roll length ft = π × (roll diameter² − core diameter²) × 1000 ÷ (48 × thickness mil)
Running minutes = scheduled minutes × uptime % ÷ 100; gross footage = line speed × scheduled minutes
Running footage = line speed × running minutes; downtime footage = gross footage − running footage
Running time per roll = roll length ÷ line speed; roll equivalents = running footage ÷ roll length

Inputs explained

Roll Outside Diameter: Measured outside diameter across the wound roll.
Core Outside Diameter: Measured outside diameter of the empty core, not its bore.
Full Web Thickness: Measured full material caliper, including any liner.
Running Line Speed: Observed web speed while the line is running.
Scheduled Production Window: Minutes allocated to this line's production plan.
Expected Line Uptime: Expected running share of scheduled time from comparable line records.

How to use the result

Best suited to rollstock inventory Estimate, rewinder run Planning, uptime comparison.
Actual winding density can change with tension, caliper variation, trapped air and compressible material. Running footage includes material later rejected; no quality yield or saleable-footage guarantee is inferred.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 280.569 (BLS, Aug 2026), up 6.6% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The producer price index for paper (not a paperboard or container index) stands at 282.266 (BLS, Aug 2026), up 10% from a year earlier. Quotes priced off last quarter's material cost miss this move.

Common questions

Should I enter the core's hole diameter? No. Enter the core's outside diameter where the first web layer touches it. The bore does not represent the material boundary.
Does the thickness include a release liner? Yes. Include every layer that is wound onto the roll. Omitting a liner overstates the estimated web length.
Why does uptime leave roll length unchanged? Uptime changes running minutes and planned footage, while the roll's geometry stays fixed. Compare roll equivalents to see how the production plan changes.
Does this estimate accepted production footage? No. Planned running footage excludes downtime but includes any material later rejected. Apply separately measured quality losses when planning accepted output.

Last reviewed 2026-10-01.