Which phones and computers work
| Device | Browser | Works |
|---|---|---|
| Android phone or tablet | Chrome, Edge, Samsung Internet | Yes |
| Windows, macOS, Linux, Chromebook | Chrome or Edge | Yes |
| iPhone and iPad | Safari, Chrome | No. Apple does not allow Web Bluetooth. Use the free Bluefy browser. |
| Firefox on any device | Firefox | No |
The page must be opened on a secure connection (https), which this site uses. Bluetooth must be on and your device must be close.
What you can connect
Any device that shares heart rate with the standard Bluetooth Heart Rate Service works: chest straps from Polar, Garmin, Wahoo and Coospo, many arm bands, and many sports watches and fitness bands that have a heart rate broadcast or "share heart rate" mode. Smartwatches such as Apple Watch keep heart rate private unless an app is used, so they may not appear in the list.
Tip: turn on broadcast mode in your watch settings, put the strap on with a little water on the pads, and close other apps that are connected to the same strap, because most straps allow one connection at a time.
Heart rate zones
| Zone | Percent of max | Feels like |
|---|---|---|
| Zone 1 | 50 to 60 | Warm up, very easy |
| Zone 2 | 60 to 70 | Easy, can talk freely |
| Zone 3 | 70 to 80 | Steady, short sentences |
| Zone 4 | 80 to 90 | Hard, a few words |
| Zone 5 | 90 to 100 | Maximum, short bursts only |
Max heart rate is estimated from age. The Tanaka formula (208 minus 0.7 times age) is usually closer than 220 minus age. For exact zones, see the heart rate calculator.
Privacy and safety
The heart rate numbers stay in your browser. They are not sent or stored. This tool is for fitness use and is not a medical device. If you feel chest pain, dizziness or severe breathlessness, stop and get medical help.