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Boat Speedometer Online

Use this boat speedometer to view your phone's speed over ground in km/h, mph and knots. It provides a GPS estimate for a boat trip without connecting to a marine speed sensor.

BOAT / GPSReady to start
-- km/h
--mph
-- knots speed over ground

YOUR CURRENT SPEED

No location reading No reading yet
Press Start to check location access

Your trip at a glance

Not started
Top speed
--km/h
Average speed
--km/h
GPS distance
--km
Elapsed time
00:00min : sec
Speed over timeLast 60 seconds
Your speed history will appear here
60s agoNow

Allow precise location when your browser asks.
Location and trip data stay in this tab. No route is saved.

Tap Start and allow precise location. Keep this page visible for speed updates.

Estimates from your phone's location. Average speed uses valid readings; GPS distance can miss movement during signal gaps. Marine readings are speed over ground, not speed through water.

Location permission help

Start lets your browser check access. If permission is already allowed, readings begin without another prompt. If the site is blocked, change its permission first; the page cannot force the browser to ask again.

  • Chrome, Microsoft Edge and Opera: open the site controls or permissions next to the address bar and allow Location for this site.
  • Mozilla Firefox: open the site's permission controls next to the address bar and clear or change a location block, then press Start again.
  • Apple Safari: check Location in this website's settings. On a Mac, also check Safari's Websites settings and system Location Services. On iPhone or iPad, check system Location Services and precise location access for the browser.

Keep device Location Services on. A private window or temporary permission may ask again. Browser permission allows a location estimate; it does not guarantee satellite reception or force use of the GPS chip.

Location stays in this tab No app or account needed Stop tracking at any time

How to check your boat speed online

  1. Open the page on your phone over HTTPS with location services enabled.
  2. Press Start and allow precise location in your browser.
  3. Wait for a reliable reading. Read current speed in km/h and mph, with knots underneath.
  4. Press Stop to end location tracking and keep the trip summary. Use Reset trip to clear it.

How do I check my boat speed in knots?

Using a phone as a boat speedometer

The boat speedometer can display movement while your phone is on a sailing boat, motorboat or other small vessel. It measures the phone's location changes or the speed supplied by the device. It does not connect to a pitot tube, paddlewheel, engine or onboard navigation system.

Secure the phone and start the tool before departure or while safely stopped. Keep navigation and collision avoidance on appropriate instruments. This page does not provide charts, depth, heading, tide data or guidance about a safe operating speed.

Why can GPS speed differ from the boat instruments?

The result is speed over ground. Wind, current and the vessel's movement relative to the water are not measured separately. A boat drifting with a current can therefore have a nonzero GPS speed even when its engine is off. A low-speed estimate can also be harder to resolve when position error is large compared with the movement.

How does this GPS speedometer calculate speed?

km/h = speed in m/s × 3.6
mph = speed in m/s × 2.2369362920544
knots = speed in m/s × 1.9438444924406
estimated speed = distance between valid positions ÷ elapsed seconds

The tool uses the speed supplied by your browser when available. To estimate speed from changes in position, it needs location readings at least two seconds apart and movement larger than their reported position error. Readings older than ten seconds or with location accuracy worse than 50 meters are not used as current speed.

Boat speed in knots, km/h and mph

A GPS speed over ground of 5 knots is 9.26 km/h and about 5.8 mph. At 12 knots the same conversions give 22.224 km/h and about 13.8 mph. A missing location reading is shown as unavailable rather than being interpreted as a boat at rest.

What do top speed, average speed and distance mean?

Top speed is the highest accepted reading in this session. Average speed divides the estimated distance by the time covered by valid readings. It includes valid zero-speed intervals and excludes signal gaps, so it can differ from distance divided by the elapsed timer. GPS distance is estimated from speed over time or changes in position after filtering location noise. It can miss movement during a signal gap and does not reproduce a mapped route.

The elapsed timer starts when the browser returns its first location reading. It includes later signal gaps and time spent with the page hidden, until you press Stop.

Coordinates and the trip summary stay in this tab's memory. They are not sent to Utilza, saved in browser storage or included in analytics events. Your browser and operating system may use their own location provider. Stop ends tracking and keeps the summary. Reset trip, starting a new trip or reloading the page clears it.

Why is my GPS speed missing or inaccurate?

  • The tool measures your phone's movement. It does not identify a vehicle or connect to its instruments.
  • Location quality and update timing depend on the device and browser. Tunnels, blocked signals and approximate-location settings can prevent useful readings.
  • Updates pause while the page is hidden. Leaving the page stops tracking. Use Reset trip to clear the summary before leaving; reloading or starting a new trip also clears it.
  • Current speed, distance and average are estimates. Signal gaps are excluded from distance and average speed; the elapsed timer includes gaps after the first location reading.
  • Marine readings are speed over ground. This page is not a navigation instrument and does not measure speed through water.

Frequently asked questions

Can I use this boat speedometer without a marine sensor?

Yes, if your phone and browser provide reliable location readings. No boat hardware is connected. The result is an estimate of movement over ground and does not replace onboard instruments.

Why can my boat show speed with the engine off?

GPS measures movement relative to Earth. A drifting boat can move with the current while its engine is off. The page cannot separate current speed from the boat's movement through the water.

Can it measure very slow boat movement?

Slow movement can be difficult to distinguish from location error. If the device supplies no speed, the page waits for enough movement between accurate fixes to estimate it. It does not force an uncertain reading to zero.

Why does the speedometer need location permission?

The browser needs permission to report the device's position and speed. If access is blocked, enable location for this site in browser and device settings, then try again. The tool cannot bypass a denied permission.

Are my coordinates or trip saved?

No. Coordinates, readings and the trip summary stay in this tab's memory and are not sent to Utilza or saved in browser storage. Stop ends tracking. Reset trip, starting a new trip or reloading the page clears the summary. Your browser's location provider has its own privacy practices.

Often used together with Boat Speedometer.