Editing Bluetooth (section)

=== Bluetooth classes and power use ===
{| class="wikitable floatright" style="text-align:right;"
|+ Bluetooth device power by class
|-
! rowspan=2 | Class
! colspan=2 | Maximum permitted power
|-
! mW
! [[dBm]]
|-
! 1
| 10–100 || +10–+20
|-
! 1.5*
| 2.5–10 || +4–+10
|-
! 2
| 1–2.5 || 0–+4
|-
! 3
| 0.01–1 || &minus;20–0
|-
| colspan="4" style="text-align:left;"| * Class{{nbsp}}1.5 included in Class{{nbsp}}1 for BR/EDR
|-
| colspan="4" style="text-align:left;"| Source: Bluetooth Core Specification revision{{nbsp}}5.3,<br>Volume{{nbsp}}6, Part{{nbsp}}A, §{{nbsp}}3, and<br>Volume{{nbsp}}2, Part{{nbsp}}A, §{{nbsp}}3, [https://www.bluetooth.com/specifications/specs/core-specification-5-3/ Bluetooth SIG]
|}
Historically, the Bluetooth range was defined by the radio class, with a lower class (and higher output power) having larger range.<ref name="bluetooth1">{{cite web |url=http://www.bluetooth.com/Pages/Basics.aspx |title=Basics {{pipe}} Bluetooth Technology Website |publisher=Bluetooth.com |date=23 May 2010 |access-date=16 October 2012 |archive-date=28 October 2012 |archive-url=https://web.archive.org/web/20121028194747/http://www.bluetooth.com/Pages/basics.aspx |url-status=dead }}</ref> The actual range of a given link depends on several qualities of both communicating devices and the [[Path loss|air and obstacles in between]]. The primary attributes affecting range are the data rate, protocol (Bluetooth Classic or Bluetooth Low Energy), transmission power, and receiver sensitivity, and the relative orientations and gains of both antennas.<ref>{{cite web|url=https://www.bluetooth.com/learn-about-bluetooth/key-attributes/range/|title=Understanding Bluetooth Range|publisher=Bluetooth SIG|access-date=29 June 2022}}</ref>

The effective range varies depending on propagation conditions, material coverage, production sample variations, antenna configurations and battery conditions. Most Bluetooth applications are for indoor conditions, where attenuation of walls and signal fading due to signal reflections make the range far lower than specified line-of-sight ranges of the Bluetooth products.

Most Bluetooth applications are battery-powered Class&nbsp;2 devices, with little difference in range whether the other end of the link is a Class&nbsp;1 or Class&nbsp;2 device as the lower-powered device tends to set the range limit. In some cases the effective range of the data link can be extended when a Class&nbsp;2 device is connecting to a Class&nbsp;1 transceiver with both higher sensitivity and transmission power than a typical Class&nbsp;2 device.<ref>{{cite web |url=https://inventionduniya.in/what-is-bluetooth-and-how-to-use-bluetooth/ |archive-url=https://web.archive.org/web/20211010085437/https://inventionduniya.in/what-is-bluetooth-and-how-to-use-bluetooth/ |url-status=dead |archive-date=10 October 2021 |title=Class 1 Bluetooth Dongle Test |publisher=Amperordirect.com |access-date=4 September 2010 }}</ref> In general, however, Class&nbsp;1 devices have sensitivities similar to those of Class&nbsp;2 devices. Connecting two Class&nbsp;1 devices with both high sensitivity and high power can allow ranges far in excess of the typical 100&nbsp;m, depending on the throughput required by the application. Some such devices allow open field ranges of up to 1&nbsp;km and beyond between two similar devices without exceeding legal emission limits.<ref name="WT41">{{cite web |url=http://www.bluegiga.com/WT41_Long_Range_Bluetooth_Module |title=WT41 Long Range Bluetooth Module |access-date=28 August 2013 |archive-date=3 July 2013 |archive-url=https://web.archive.org/web/20130703045646/http://www.bluegiga.com/WT41_Long_Range_Bluetooth_Module |url-status=live }}</ref><ref name="BluBear">{{cite web |url=http://www.lesswire.com/en/products/embedded-wireless-modules/bluetooth/bluebear/overview/ |archive-url=https://web.archive.org/web/20130717051641/http://www.lesswire.com/en/products/embedded-wireless-modules/bluetooth/bluebear/overview/ |url-status=dead |archive-date=17 July 2013 |title=BluBear Industrial Long Range Bluetooth 2.1 Module with EDR  }}</ref><ref name="OBS433">{{cite web |url=http://www.connectblue.com/products/classic-bluetooth-products/classic-bluetooth-modules/bluetooth-serial-port-module-obs433/ |title=OEM Bluetooth Serial Port Module OBS433 |access-date=28 August 2013 |archive-date=16 July 2013 |archive-url=https://web.archive.org/web/20130716065225/http://www.connectblue.com/products/classic-bluetooth-products/classic-bluetooth-modules/bluetooth-serial-port-module-obs433/ |url-status=live }}</ref>