Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Passage time (hours)
7.50
Speed over ground (kts)
6.00
Statute miles
51.8
Kilometers
83.3
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter distance (nm).
- 2Enter boat speed (kts).
- 3Enter current with (+) / against (−) (kts).
- 4Read your passage time (hours) on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Enter nautical miles and speed over ground to get passage hours, plus a current-adjusted estimate.
Worked example
Using the values the calculator loads with:
Inputs
- Distance: 45 nm
- Boat speed: 6.5 kts
- Current with (+) / against (−): -0.5 kts
Results
- Passage time (hours): 7.5
- Speed over ground (kts): 6
- Statute miles: 51.8
- Kilometers: 83.3
What each field means
Inputs
- Distance (nm)
- The distance used in the calculation, measured in nm. Starts at 45 nm so you have a working example on load.
- Boat speed (kts)
- The boat speed used in the calculation, measured in kts. Starts at 6.5 kts so you have a working example on load.
- Current with (+) / against (−) (kts)
- The current with (+) / against (−) used in the calculation, measured in kts. Starts at -0.5 kts so you have a working example on load.
Results
- Passage time (hours)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Speed over ground (kts)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Statute miles
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Kilometers
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the nautical distance & eta calculator work?
Enter nautical miles and speed over ground to get passage hours, plus a current-adjusted estimate.
What do I need to enter?
3 values: distance, boat speed, and current with (+) / against (−). Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the passage time (hours) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Nautical Distance & ETA Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/nautical-distance
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/nautical-distance" target="_blank" rel="noopener">Nautical Distance & ETA Calculator — RevenueLab</a> (2026).</p>
Source: [Nautical Distance & ETA Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/nautical-distance) (2026).