Ship Displacement Calculator

Work out ship displacement instantly with clear inputs, formula shown and shareable results.

About Ship Displacement Calculator

Displacement is the mass of water the hull pushes aside, equal to the underwater volume times water density. That volume is length times beam times draft times the block coefficient, and sea water at 1.025 t/m3 makes a ship float about 2.5% higher than the same hull in fresh water.

Formula

Displacement

Volume = L x B x T x Cb; displacement = volume x 1.025 t/m3 in sea water

Worked example

With the default values below, Ship Displacement Calculator returns Displacement of 10,361.52. Change any input above and every figure here is recalculated in your browser.

Inputs used

Length on waterline: 120 m
Beam: 18 m
Draft: 6.5 m
Block coefficient: 0.72

Results

Displacement: 10,361.52 t
Displaced volume: 10,108.80 m³
Displacement in fresh water: 10,108.80 t
Tonnes per centimetre immersion: 19.26 t/cm

Step by step

1Values used
2Displacement
3Displacement= 10,361.52 t
4Displaced volume= 10,108.80 m³
5Displacement in fresh water= 10,108.80 t
6Tonnes per centimetre immersion= 19.26 t/cm

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 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Marine results are planning estimates only. Verify against the vessel's approved stability booklet, loading manual, class society rules and applicable maritime regulations before loading or sailing.

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

Marine results are planning estimates only. Verify against the vessel's approved stability booklet, loading manual, class society rules and applicable maritime regulations before loading or sailing.

Frequently Asked Questions

Why does the ship sit deeper in fresh water?

Fresh water is less dense, so a greater volume must be displaced to support the same mass — the origin of the fresh water allowance on the load line.

What is TPC used for?

Tonnes per centimetre tells you how much cargo changes the draft, which is the basis of a draft survey.