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Speed is worked out on your device and never uploaded. The map loads tiles for your area from OpenStreetMap and Esri.
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Large knots readout, top speed, average speed and distance. Works offline once loaded, which makes it handy on the water and in airplane mode.
How to Measure Your Speed in Knots
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1. Load the page before you leave
Open it while you still have signal (or install it as an app). After that, GPS works with no mobile data.
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2. Allow precise location
Choose Allow and keep precise location switched on. KNOTS is preselected on this page.
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3. Keep a clear view of the sky
Below deck, inside a cabin or in a pocket, the signal weakens. Near a window or out on deck the reading is much steadier.
How Fast Is a Knot?
The nautical mile is tied to the shape of the Earth: it was originally one minute of latitude. That makes it convenient for navigation charts, so ships, aircraft and weather forecasts for wind all use knots. The name comes from the old chip log: sailors let out a line with knots tied at regular intervals and counted how many passed through their hands in a set time.
| Knots | km/h | mph | Typical example |
|---|---|---|---|
| 3 kn | 5.6 km/h | 3.5 mph | Touring kayak |
| 6 kn | 11.1 km/h | 6.9 mph | Sailboat cruising |
| 20 kn | 37.0 km/h | 23.0 mph | Cruise ship |
| 35 kn | 64.8 km/h | 40.3 mph | Fast motorboat |
| 150 kn | 277.8 km/h | 172.6 mph | Airliner around takeoff |
| 480 kn | 889.0 km/h | 552.4 mph | Airliner cruise (ground speed varies with wind) |
Convert other values with the speed converter.
Speed Over Ground vs. Speed Through Water
For arrival times and fuel planning, SOG is what matters. For sail trim and hull performance, sailors also watch STW. In the air the same idea applies: GPS shows ground speed, while the aircraft’s instruments show airspeed, and the difference is the wind. See flight speed for more.
Where a Knots Speedometer Helps
- Boats and jet skis: check your speed in no-wake zones and speed-restricted waters — see the boat speedometer.
- Kayaks, canoes and paddleboards: track pace and distance on a trip.
- Ferries and cruise ships: see how fast the ship is moving from the deck.
- Flights: see your ground speed in airplane mode from a window seat.
Frequently Asked Questions About Knots
How fast am I going in knots right now?
Tap Start at the top of this page and allow location access. Your speed over ground appears in knots on the gauge.
Which is faster, 1 knot or 1 mph?
1 knot is faster. It equals about 1.15 mph or 1.852 km/h.
How do I convert knots to km/h or mph?
Multiply knots by 1.852 for km/h, or by 1.151 for mph. For example, 25 knots ≈ 46.3 km/h ≈ 28.8 mph.
Does it work at sea without a phone signal?
Yes. Once the page is loaded, GPS works without mobile data or Wi-Fi. Keep the phone where it can see the sky.
Can I use it on a plane?
Usually yes. In airplane mode GPS can still receive satellites near a window, though a few phones turn GPS off in airplane mode. It shows ground speed, not airspeed.