How to Change Dash Cam Speed Units Between mph and km/h

Why the speed unit matters

The speed value burned into dash cam footage is a practical record of where and how fast you were driving. If a camera is left on km/h while you drive in an mph country, every clip will show a number that looks lower than the speed on the road, and it may be hard to explain later. The opposite problem appears when a camera set to mph is used in a km/h country: the overlay looks too high.

Changing the unit is not part of the recording format. The dash cam stores the video file, and it paints the speed text into the frame using GPS data. Reselecting the unit does not delete clips. If you are not sure whether your camera has GPS, see how GPS works in dash cams.

Unit settings are a small thing you should settle while parked. Restraint on menu work matters: IIHS reports that manipulating a cellphone has been linked to increased crash risk, and the CDC notes that motor vehicle crashes are a leading cause of death but are preventable.

Check GPS before you change the unit

The speed unit setting lives inside the GPS section, so the camera needs to know that a GPS receiver is present. Some dash cams have a built-in GPS module, and others use an external puck. On models without any GPS option, the speed overlay may not be available at all, and the unit menu may be hidden. For the broad picture, compare dash cams with GPS before you buy.

Before changing the unit, check the satellite or GPS icon on the live view. If the icon is empty, park with a clear view of the sky and wait for a fix. Then open the speed unit setting. On many models, the video overlay will not update until the camera sees the satellite icon and you have confirmed the new unit.

If the icon never appears, or the speed value stays as dashes, follow the steps in how to fix a dash cam GPS signal before blaming the unit setting.

Where the unit setting is in the menu and app

The usual path is Menu or Settings, then GPS or System, then a label such as Speed Unit, Unit, Units, or Speed Display. Some cameras place the option under General or Display. Look near time zone, clock format and speed compensation, because firmware authors group regional options together. For another clock-related choice, see how to set the dash cam clock format to 12 or 24 hours.

On a Wi-Fi dash cam, the unit control is often mirrored in the phone app. Open Camera Settings or the gear icon on the camera page, find the GPS section, and select mph or km/h. The app then sends the choice to the camera. If the app does not show the option, change it on the camera itself and reconnect, as explained in dash cam Wi-Fi apps.

• Look for these exact words if the menu is deep: Speed Unit, Unit, Units, Speed Display, GPS Unit, Units of Measure.
• If GPS is not its own menu, check System, General, Camera, or Setup.
• In the app, open the gear icon on the camera page, not the app's home screen.

How switching units affects the recording, alerts and logs

Switching the unit changes only the speed text in the video. It does not change resolution, frame rate, bitrate or file format. The GPS location and heading remain the same, and the speed value is converted to the unit you choose.

Some cameras use the same setting for speed-related alerts, such as speed camera warnings or overspeed beeps. If your model has those alerts, review one alert after changing units to confirm the new unit is used.

GPS logs may be stored separately from the overlay. In many cameras, changing the unit does not rewrite the internal log, and mapping programs let you choose the display unit when you export the data. See how to export dash cam GPS logs to a map.

If your dash cam receives speed from an OBD adapter rather than from GPS, the unit setting may also control that value. Match the dash cam unit to the car's instrument cluster unit, and read about GPS speed vs OBD speed for more detail.

Verify the change on a short drive

After you choose mph or km/h, take a short drive and check the overlay. At a steady cruise, the displayed speed should be close to the vehicle's speedometer. If the overlay shows the old unit, restart the camera and let the GPS reconnect before changing it again.

If the displayed speed is clearly far from the speedometer, look for a speed calibration or speed compensation option in the same GPS section. Treat the dash cam speed as a video reference rather than a certified speedometer.

Playback tools can help if you want to look at the overlay later; how to play dash cam footage on a TV covers one way to review clips.

What to do if there is no speed unit option

Most dash cams with GPS provide mph and km/h, but some firmware versions hide the choice until they are updated. Check the maker's support page for a firmware update and look again. Updating can also add language options and regional settings, as covered in dash cam firmware update.

If the menu still has no unit option, consult the manual or contact the manufacturer. If the model really cannot change units, you may be able to turn the speed overlay off and keep the timestamp and GPS data. The dash cam video overlay article explains how much of the on-screen text you can control.

Before you buy, look for GPS and a unit choice on the spec sheet. Dash cams with a companion app are easier to change when you cross borders, so compare dash cams with GPS and Wi-Fi dash cams for models that fit how you drive.

What to pick for your use

Questions

How do I change my dash cam from mph to km/h?

Open the menu and look for GPS or System settings, then choose Speed Unit, Unit, or Speed Display and select km/h. On a Wi-Fi model, the same option is usually in the app's camera settings. Restart the camera if the overlay is slow to update.

Why does my dash cam still show km/h after I picked mph?

The camera may need a GPS fix or a restart to refresh the overlay. Park with a clear view of the sky, let the satellite icon appear, then power the camera off and on. Check the firmware if the setting will not stick.

Does changing speed units alter the recorded GPS track?

No. The unit choice normally changes only the speed text shown in the video. The underlying GPS log is stored by the camera and can be displayed in your preferred unit when you view or export it.

Can I switch speed units from the smartphone app?

On Wi-Fi dash cams, yes. Open the camera settings in the app, find the GPS section, and select mph or km/h. If the option is missing, change it on the camera, then reconnect the app.

What if my dash cam does not offer mph or km/h?

Update the firmware first, then check the manual or contact the manufacturer. If the model still has no unit option, you can often turn the speed overlay off and keep the rest of the GPS data.

Are speed camera alerts affected by the unit setting?

When your camera provides speed-related alerts, the alert values usually follow the same unit setting as the overlay. After changing units, test one alert or check the manual to confirm.