Skip to content
ENExplore Calculators

Voyage Time Calculator

Work out voyage time instantly with clear inputs, formula shown and shareable results.

About Voyage Time Calculator

Passage time is distance divided by the speed actually made good, which is service speed reduced by a weather and current allowance of typically 3-8%. Adding port time at each end gives the round figure used for scheduling, chartering and bunker planning.

Formula

Voyage time

sea time = distance / (speed x (1 - weather allowance)); total = sea time + port time

Worked example

With the default values below, Voyage Time Calculator returns Total voyage duration of 10.20. Change any input above and every figure here is recalculated in your browser.

Inputs used

Voyage distance
2,650 nm
Service speed
13.5 kt
Weather and current allowance
6 %
Port time at each end
36 h

Results

Total voyage duration
10.20 days
Days at sea
8.70 days
Sea passage time
208.83 h
Effective speed made good
12.69 kt

Step by step

  1. 1Values used
  2. 2Voyage time
  3. 3Total voyage duration= 10.20 days
  4. 4Days at sea= 8.70 days
  5. 5Sea passage time= 208.83 h
  6. 6Effective speed made good= 12.69 kt

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 include a weather allowance?

Trial speed is measured in calm water. Real passages lose speed to wind, sea state, hull fouling and adverse current.

How is speed made good different from log speed?

Log speed is through the water; speed made good is over the ground and includes the current, which is what determines arrival time.

Related Calculators

Voyage Time Calculator – Calculate Total voyage duration