There are different versions of Bluetooth. The earliest version (1.0) had a theoretical maximum range of 10m. In versions 2.0 and 3.0, that was extended up to a notional range of 30m. With version 4.0 the figure went up again, to 60m, with version 5.0 seeing yet another rise, to 240m.
Those, of course, are entirely theoretical figures, which assume that there is no obstruction in the signal path and no interference from other radio devices in the area. In practice, I wouldn't rely on Bluetooth devices to reliably maintain connection over much more than about a quarter of those figures.
Most Bluetooth devices in use these days will probably be using either Bluetooth 3.0 or 4.0, with v.5.0 devices only just coming onto the market. However some people have probably still got Bluetooth devices that use v.1.0 or v.2.0.