On / Off Hire Bunker & Condition Survey
Joint bunker and condition assessment at the start or end of a charter period, establishing a clear record for both parties.
Free tool
Off-Hire & Bunker Settlement Calculator
Off-hire period to the minute across time zones, the hire for that period, and the value of the bunker difference between delivery and redelivery. Arithmetic only — it runs in your browser and nothing you type is sent anywhere.
Arithmetic aid, not a legal or contractual opinion. This calculator does not decide whether a vessel was off hire, which price applies to which quantity, or how bunker values and hire are settled or netted. Your charter party does. It multiplies and subtracts the figures you enter and shows every step.
How the figures are calculated
- Off-hire period. Each time is converted to UTC using the offset you chose (local time minus offset), then the two UTC instants are subtracted. The result is kept in whole minutes. Your computer's own time zone is never used.
- Same-clock check. If the two offsets differ, the result also shows what the same entries would give if both were read on one clock — the usual source of a one- or two-hour disagreement.
- Hire for the period. Daily hire × minutes ÷ 1,440. No rounding to the hour or the day.
- Fuel consumed during off-hire. Quantity × the price you entered for that fuel, per grade, then summed.
- Bunker difference. Per grade: ROB at redelivery − ROB at delivery (tonnes), and ROB at redelivery × redelivery price − ROB at delivery × delivery price (USD). A negative figure means less, or less value, on board at redelivery than at delivery. The tool does not say which party that favours.
- Rounding. All arithmetic runs at full precision; money is rounded to the cent (half away from zero) only when displayed.
The results are only as good as the figures entered. ROB itself is a measured quantity: an independent on / off hire bunker survey at delivery and redelivery gives both parties the same starting figures.
Frequently Asked Questions
Why do owner and charterer often get different off-hire times from the same log?
Usually because the two timestamps are read on different clocks. A vessel that changes ship's time between going off hire and coming back on hire, or one side working in UTC and the other in local time, will produce a gap of one or more hours. Entering each time with the UTC offset in force at that moment, as this calculator asks, removes that source of difference.
How are part days handled?
The period is counted in whole minutes between the two UTC instants and divided by 1,440 to give days. Hire for the period is the daily rate multiplied by that figure. Nothing is rounded until the result is displayed, and then only to the cent.
Does the calculator say who owes what?
No. It does not decide whether the vessel was off hire, which price applies to which quantity, or how bunker values and hire net against each other. Those follow your charter party. The calculator multiplies and subtracts the figures you enter and shows every step, so both sides can check the same arithmetic.
Is anything I enter sent or stored?
No. The calculation runs entirely in your browser. Nothing you type is transmitted, logged or stored.
Related Services
Damage & Claims Support
Independent assessment following damage or an incident, supporting claims handling and repair planning.
Engine Room Defective Survey
For a specific engine room defect or issue already identified aboard — this survey investigates probable cause and implications, rather than reviewing overall condition.
This calculator is provided for general arithmetic convenience only. It is not legal advice, a contractual interpretation, or a substitute for the charter party, the vessel's logs or an independent survey report.