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Web setpoint
Web Tension Force Calculator
Turn a material or process tension stated per unit width into the total force carried across the running web.
What this calculator solves
Material guidance often states tension as N/mm, N/m or PLI, while load cells, dancers, brakes and torque calculations need total force. This conversion bridges those two specifications before an operator enters a setpoint or selects a sensing range.
Inputs and units
Measure the active web after slit trim. N/mm multiplied by width in millimetres gives newtons; N/m uses width in metres; PLI uses width in inches and returns pounds-force before conversion to newtons.
Calculation method
Total tension equals tension per unit width multiplied by web width in the matching unit. The tool also reports lbf so a metric material specification can be checked against imperial controls.
Worked production example
A 1,000 mm paper web is approved at 0.20 N/mm. Total tension is 200 N, or about 44.96 lbf. That is the force carried by the complete web and the starting value for torque and sensor calculations.
How to use the result
Compare total force with the usable—not merely maximum—range of the installed sensing system. Then pass the force to the Winding Torque Calculator at the current roll diameter.
Common production mistakes
Do not multiply a PLI value by millimetres or use gross master-roll width after trimming. A setpoint copied from another substrate is not a material limit; document its source and trial history.
Assumptions and limitations
This is a unit-and-width conversion, not a recommendation for paper, film, foil or laminate. It does not account for span dynamics, friction, acceleration or cross-web tension variation.
Related workflow and sources
Continue with Taper Tension and the web tension setup guide. Montalvo defines web tension as force across the web and publishes application calculators and unit references. Montalvo tension basics. Last reviewed: 2026-08-27.