Seafarers Tax Calculator

Seafarers Tax Calculator – Know Your SED Position
Know exactly where you stand with your Seafarers Earnings Deduction (SED) — before it’s too late.
Track your voyages, calculate your qualifying days, and see your Days in Hand (DIH) and fail date in real time.
Built offshore, for offshore workers.

Why this matters
Most seafarers don’t realise they’re short on days until the end of the tax year.
By then… it’s too late.
This app shows you:
How many qualifying days you have
How close you are to failing
The exact date your claim could fall short
No spreadsheets. No guesswork.
📊 Key Features
SED Tracking Made Simple
Log voyages and holidays in seconds
Automatic qualifying day calculation
Works fully offline (perfect offshore)
Days in Hand (DIH)
See how much buffer you have
Know instantly if you’re close to the edge
Fail Date Prediction
See the exact date your claim could fail
Stay ahead instead of reacting too late
HMRC-Ready Records
Keep a clear log of your trips
Export CSV and PDF reports for accountants or HMRC
Smart Reminders
Get alerts before your fail date
Stay in control of your claim all year round
Document Storage
Store discharge books, payslips, and records
Keep everything in one place when it matters
🚢 Built for Offshore Reality
Works without signal or WiFi
No login required
No complicated setup
Designed for real offshore rotations
👷 Who it’s for
Offshore workers
Seafarers claiming SED
Wind, oil & gas, marine crews
Anyone needing to track qualifying days accurately
💡 Simple but powerful
This isn’t about features.
It’s about one thing:
Knowing your position before you submit your claim.
🔐 Premium Features
Upgrade to unlock:
Days in Hand (DIH)
Fail Date tracking
Export reports
Smart alerts
Extra document storage
Final word
If this app helps you avoid losing your SED claim…
it’s already paid for itself.

⚠️ Disclaimer
The app is designed as a practical tracking tool and does not replace professional tax advice.