Web Tension Calculator

Work out web tension instantly with clear inputs, formula shown and shareable results.

About Web Tension Calculator

Web tension is specified per unit width so it scales with the material, not the machine: total tension is tension per millimetre x web width. Dividing by the cross-section gives stress, and stress over modulus gives the elastic stretch, which must stay well below yield to avoid permanent elongation and registration drift.

Formulas

Web tension

Total tension (N) = tension per mm width x web width (mm)

Stress and strain

Stress = tension / (width x thickness); strain % = stress x 100 / modulus

Worked example

With the default values below, Web Tension Calculator returns Total Web Tension of 500.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Web Widthminimum 0.01 mm: 1,000 mm
Web Thicknessminimum 0.01 micron: 80 micron
Tension Settingminimum 0.001 N per mm width: 0.5 N per mm width
Material Modulusminimum 0.01 MPa: 3,000 MPa

Results

Total Web Tension: 500.00
Web Stress: 6.2500
Elastic Strain: 0.20833%
Web Cross-Section: 80.0000

Step by step

1Values used
2Web tension
3Stress and strain
4Total Web Tension= 500.00
5Web Stress= 6.2500
6Elastic Strain= 0.20833
7Web Cross-Section= 80.0000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What tension setting should be used?

Typically 10-25% of the material's yield strength expressed per unit width — around 0.3-0.9 N/mm for common packaging films and 1-3 N/mm for paperboard. Always check the supplier's data sheet.

What goes wrong if tension is too high or too low?

Too high stretches the web, causes registration errors, telescoping rolls and web breaks. Too low causes wrinkles, wander, poor winding and slack loops at splices.