Crew & reference
Sea-Service Calculator
Add every contract from your discharge book. Overlaps count once, and you get days, months and decimal months under the rule your administration uses.
| Vessel or capacity | Sign on | Sign off | Actions |
|---|---|---|---|
| Continuous period | From | To | Days |
|---|---|---|---|
| MV Example (AB), MV Example (OS) | 2024-01-01 | 2024-04-30 | 121 |
| MV Example (AB) | 2024-05-10 | 2024-06-30 | 52 |
Shore periods between continuous blocks: 9 days. Counting rules and the month convention are set by your flag state and certifying authority. This calculator applies the rule you select; it does not issue or verify service records.
Method
Counting rules are explicit.
Two rules are common. Inclusive counts sign-on and sign-off days; exclusive counts the whole days between them. The month convention is an input too.
Overlaps
Contracts that overlap are merged, so the shared days are counted once. The overlap total is shown.
Shore gaps
Gaps between continuous blocks are reported separately and are not counted as service.
Your rule
Certifying authorities set the rule. Check the form instructions before you submit.
Get in touch
Keep the record on your device.
Save the calculation to My Desk and export it whenever you need it.