MCA Sea Time Calculator
Track qualifying sea service days from multiple voyages. Enter your periods on board, apply any non-qualifying deductions, and compare your total to your target.
| Vessel / Trip (optional) | Start Date | End Date | Non-Qualifying Days | Qualifying Days | Action |
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What is MCA sea time?
In simple terms, MCA sea time (often called sea service) is the amount of qualifying time you have served on board a vessel while performing relevant duties. The Maritime and Coastguard Agency (MCA) uses this service record when assessing eligibility for many UK maritime certificates.
Different certificates and routes have different sea service requirements. That means your first step is always to confirm the current requirement for your specific path (for example, deck officer progression, engineering route, or a small commercial vessel pathway).
Why a sea time calculator helps
Most mariners do not complete sea service in one clean block. Real careers include multiple contracts, leave periods, vessel changes, refits, and training phases. A calculator gives you a fast and transparent way to:
- Total service across many voyages.
- Apply deductions where needed.
- Track progress toward your target number of days.
- Spot shortfalls early so you can plan your next contract.
How this calculator works
1) Add each voyage period
Enter your start and end date for every period you want counted. You can add as many rows as you need.
2) Enter any non-qualifying days
If part of a period should not be counted (for example, extended leave off vessel, specific non-eligible days, or administrative deductions), enter those days in the row. The calculator subtracts them from the raw date range.
3) Calculate totals and compare against your target
Click Calculate Sea Time to see your total qualifying days, equivalent months, and remaining days to target.
Important counting notes
- Inclusive counting: If enabled, both your start and end dates are counted.
- Date order: End date must be the same day or later than start date.
- Deductions: Non-qualifying days cannot exceed raw days in that row.
- Rounding: Month estimates are shown for planning; official assessments may use different standards.
Before submitting an MCA application
A calculator is excellent for planning, but your application still depends on formal evidence. Keep your records organized and legible:
- Discharge book entries and sea service testimonials.
- Company letters confirming vessel details and service dates.
- Training and watchkeeping records where required.
- Any supporting documents referenced in the latest MCA guidance notes/MSNs.
Common mistakes to avoid
Mixing qualifying and non-qualifying periods
If your contract includes time that does not qualify, separate it clearly and document why.
Using outdated requirements
MCA requirements can change. Always check the latest official notice before relying on any online tool.
Not keeping backup evidence
Keep digital scans and physical copies. Missing evidence can delay your application even if your totals are correct.
Quick planning strategy
A practical way to stay on track is to recalculate at the end of every contract. Update your sea service total, compare it with your certification goal, and identify your remaining days. This turns career progression into a measurable roadmap.
Final reminder
Use this page as a planning tool, not legal advice. For official eligibility and interpretation, refer directly to current MCA publications and, when needed, your training provider or company crewing department.