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Calcimator

Tonnage (GT/NT) Calculator

Calculate gross tonnage and net tonnage from enclosed volume using the ITC 69 convention.

Inputs

ft³
ft³
ft
ft

Results

Gross Tonnage (GT)

181.94

Net Tonnage (NT)

84.76

GT/NT Ratio2.15
Volume (m³)707.9 m³
How to Use This Calculator
  1. Enter the total enclosed volume (all enclosed spaces) and cargo space volume in cubic feet.
  2. Input the molded draft and molded depth in feet, and the number of passenger berths.
  3. Review the Gross Tonnage (GT) and Net Tonnage (NT) computed per ITC 69 convention.
  4. GT determines port fees, safety equipment requirements, and crew manning rules.
  5. NT affects canal dues and fishing licenses — consult a surveyor for official certification.

How the result changes with Total Enclosed Volume

Total Enclosed VolumeGross Tonnage (GT)Net Tonnage (NT)
5,000,09042,903.6212,871.09
17,500,065155,552.6746,665.8
32,500,035293,831.188,149.33
45,000,010410,444.49123,133.35

What each input means

Total Enclosed Volume
Total volume of all enclosed spaces in cubic feet.
Cargo Space Volume
Volume of cargo holds and spaces.
Molded Draft
Molded draft at summer load line.
Molded Depth
Molded depth measured at amidships.
Passenger Berths
Number of passenger berths (0 for cargo vessels).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Total Enclosed Volume = 25000, Cargo Space Volume = 15000, Molded Draft = 8, Molded Depth = 12 = 5 input(s) provided
  2. Calculate Gross Tonnage
    Gross Tonnage
    181.94 = 181.94
  3. Calculate Net Tonnage
    Net Tonnage
    84.76 = 84.76
  4. Calculate GT/NT Ratio
    GT/NT Ratio
    2.15 = 2.15
  5. Calculate Volume
    Volume
    707.9 = 707.9

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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