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Calcimator

Paper Strength Calculator

Calculate paper strength indices (tensile, tear, burst) from raw test data. Includes breaking length, TEA, and fold endurance estimates.

Inputs

%

Results

Tensile index (N·m/g)

56.25

Tear index (mN·m²/g)10
Burst index (kPa·m²/g)3.5
Breaking length (km)5.73
TEA index (J/g)0.98
Fold endurance (est.)517
Strength rating2
How to Use This Calculator
  1. Enter the paper basis weight (GSM) of the sample you tested.
  2. Input tensile strength (kN/m), tear strength (mN), and burst strength (kPa) from lab results.
  3. Enter stretch at break (%) from the tensile test.
  4. Review normalized Tensile Index, Tear Index, Burst Index, and Breaking Length (km).
  5. Use Strength Rating (Poor/Fair/Good/Excellent) and Fold Endurance for quality classification.

How the result changes with Basis weight (GSM)

Basis weight (GSM)Tensile index (N·m/g)
5976.27
18224.73
32913.68
4519.98

What each input means

Basis weight (GSM)
Paper grammage in grams per square meter.
Tensile strength (kN/m)
Tensile breaking force per unit width (TAPPI T 494).
Tear strength (mN)
Elmendorf tear strength in millinewtons (TAPPI T 414).
Burst strength (kPa)
Mullen burst strength in kilopascals (TAPPI T 403).
Stretch at break (%)
Elongation at break as a percentage.

What each result means

Tensile index (N·m/g)
Tensile strength normalized by grammage.
Tear index (mN·m²/g)
Tear strength normalized by grammage.
Burst index (kPa·m²/g)
Burst strength normalized by grammage.
Breaking length (km)
Length of paper strip that would break under its own weight.
TEA index (J/g)
Tensile Energy Absorption per unit grammage.
Fold endurance (est.)
Estimated MIT double folds before failure.
Strength rating
0 = Poor, 1 = Fair, 2 = Good, 3 = Excellent.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Basis weight (GSM) = 80, Tensile strength (kN/m) = 4.5, Tear strength (mN) = 800, Burst strength (kPa) = 280 = 5 input(s) provided
  2. Calculate Tensile index
    Tensile index = (tensileKNPerM * 1000) / basisWeightGSM
    56.25 = 56.25
  3. Calculate Tear index
    Tear index = tearMN / basisWeightGSM
    10 = 10
  4. Calculate Burst index
    Burst index = burstKPa / basisWeightGSM
    3.5 = 3.5

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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