Orders of magnitude (from wikipedia):
420 dBm 1×1039 W Cygnus A, the most powerful known source of radio waves [3]
306 dBm 3.846×1026 W Total power output of the Sun[4]
80 dBm 100 kW Typical transmission power of FM radio station with 50-kilometre (31 mi) range
62 dBm 1.588 kW = 1,588 W 1,500 W is the maximal legal power output of a U.S. ham radio station.[5]
60 dBm 1 kW = 1,000 W Typical combined radiated RF power of microwave oven elements
55 dBm ~300 W Typical single-channel RF output power of a Ku-band geostationary satellite
50 dBm 100 W Typical total thermal radiation emitted by a human body, peak at 31.5 THz (9.5 µm)
Typical maximal output RF power from a ham radio HF transceiver
40 dBm 10 W Typical PLC transmission power
37 dBm 5 W Typical maximal output RF power from a handheld ham radio VHF/UHF transceiver
36 dBm 4 W Typical maximal output power for a citizens band radio station (27 MHz) in many countries
33 dBm 2 W Maximal output from a UMTS/3G mobile phone (Power class 1 mobiles)
Maximal output from a GSM850/900 mobile phone
30 dBm 1 W = 1000 mW
DCS or GSM 1,800/1,900 MHz mobile phone. EIRP IEEE 802.11a (20 MHz-wide channels) in either 5 GHz subband 2 (5,470–5,725 MHz) provided that transmitters are also IEEE 802.11h-compliant, or U-NII-3 (5,725–5,825 MHz). The former is EU only, the latter is US only. Also, maximal power allowed by the FCC for American amateur radio licensees to fly radio-controlled aircraft or operate RC models of any other type on the amateur radio bands in the US.[6]
29 dBm 794 mW
28 dBm 631 mW
27 dBm 500 mW Typical cellular phone transmission power
Maximal output from a UMTS/3G mobile phone (Power class 2 mobiles)
26 dBm 400 mW
25 dBm 316 mW
24 dBm 251 mW Maximal output from a UMTS/3G mobile phone (Power class 3 mobiles)
1,880–1,900 MHz DECT (250 mW per 1,728 kHz channel). EIRP for wireless LAN IEEE 802.11a (20 MHz-wide channels) in either the 5 GHz subband 1 (5,180–5,320 MHz) or U-NII-2 and -W ranges (5,250–5,350 MHz & 5,470–5,725 MHz respectively). The former is EU only, the latter is US only.
23 dBm 200 mW EIRP for IEEE 802.11n wireless LAN 40 MHz-wide (5 mW/MHz) channels in 5 GHz subband 4 (5,735–5,835 MHz, US only) or 5 GHz subband 2 (5,470–5,725 MHz, EU only). Also applies to 20 MHz-wide (10 mW/MHz) IEEE 802.11a wireless LAN in 5 GHz subband 1 (5,180–5,320 MHz) if also IEEE 802.11h-compliant (otherwise only 3 mW/MHz ? 60 mW when unable to dynamically adjust transmission power, and only 1.5 mW/MHz ? 30 mW when a transmitter also cannot dynamically select frequency).
22 dBm 158 mW
21 dBm 125 mW Maximal output from a UMTS/3G mobile phone (Power class 4 mobiles)
20 dBm 100 mW EIRP for IEEE 802.11b/g wireless LAN 20 MHz-wide channels in the 2.4 GHz Wi-Fi/ISM band (5 mW/MHz).
Bluetooth Class 1 radio. Maximal output power from unlicensed AM transmitter per U.S. FCC rules 15.219[7]
19 dBm 79 mW
18 dBm 63 mW
17 dBm 50 mW
15 dBm 32 mW Typical wireless LAN transmission power in laptops
10 dBm 10 mW
7 dBm 5.0 mW Common power level required to test the automatic gain control circuitry in an AM receiver
6 dBm 4.0 mW
5 dBm 3.2 mW
4 dBm 2.5 mW Bluetooth Class 2 radio, 10 m range
3 dBm 2.0 mW
2 dBm 1.6 mW
1 dBm 1.3 mW
0 dBm 1.0 mW = 1000 µW Bluetooth standard (Class 3) radio, 1 m range
-1 dBm 794 µW
-3 dBm 501 µW
-5 dBm 316 µW
-10 dBm 100 µW Maximal received signal power of wireless network (802.11 variants)
-13 dBm 50.12µW Dial Tone for the Precise Tone Plan found on public switched telephone networks in North America
-20 dBm 10 µW
-30 dBm 1.0 µW = 1000 nW
-40 dBm 100 nW
-50 dBm 10 nW
-60 dBm 1.0 nW = 1000 pW The Earth receives one nanowatt per square metre from a magnitude +3.5 star[8]
-70 dBm 100 pW
-73 dBm 50.12pW "S9" signal strength, a strong signal, on the S meter of a typical ham or shortwave radio receiver
-80 dBm 10 pW
-100 dBm 0.1 pW Minimal received signal power of wireless network (802.11 variants)
-111 dBm 0.008 pW = 8 fW Thermal noise floor for commercial GPS single-channel signal bandwidth (2 MHz)
-127.5 dBm 0.178 fW = 178 aW Typical received signal power from a GPS satellite
-174 dBm 0.004 aW = 4 zW Thermal noise floor for 1 Hz bandwidth at room temperature (20 °C)
-192.5 dBm 0.056 zW = 56 yW Thermal noise floor for 1 Hz bandwidth in outer space (4 kelvins)
