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dBm, or deci Bells milliwatt, what does it mean?

9 January 2022

Often when dealing with electronics you will see the measurement dBm, and if you know about how dB works in general you can easily get the gist of what it is saying. But, unlike most of our dB readings, dBm is actually anchored to the value of a milliwatt. Why does this matter? It makes it easier to compare disparate systems, or engineer connections between them. For instance, I used dBm to decide how many dB of attenuation I had to add to my HF radio to be able to pipe it output into my SDR so I could see what my signal looked like.

So without any further ado, let me show my annoted dBm to wattage chart that includes both useful info, and some useless trivia.

dBm to Wattage Chart
dBmWattsHF S MeterVHF S MeterComments
-150 dBm1.00 aW
-149 dBm1.26 aW
-148 dBm1.58 aW
-147 dBm2.00 aW
-146 dBm2.51 aW
-145 dBm3.16 aW
-144 dBm3.98 aW
-143 dBm5.01 aW
-142 dBm6.31 aW
-141 dBm7.94 aWS1
-140 dBm10.00 aW
-139 dBm12.59 aW
-138 dBm15.85 aW
-137 dBm19.95 aW
-136 dBm25.12 aW
-135 dBm31.62 aWS2
-134 dBm39.81 aW
-133 dBm50.12 aW
-132 dBm63.10 aW
-131 dBm79.43 aW
-130 dBm100.00 aW
-129 dBm125.89 aWS3
-128 dBm158.49 aW
-127 dBm199.53 aW
-126 dBm251.19 aW
-125 dBm316.23 aW
-124 dBm398.11 aW
-123 dBm501.19 aWS4
-122 dBm630.96 aW
-121 dBm794.33 aWS1
-120 dBm1.00 fW
-119 dBm1.26 fW
-118 dBm1.58 fW
-117 dBm2.00 fWS5
-116 dBm2.51 fW
-115 dBm3.16 fWS2
-114 dBm3.98 fW
-113 dBm5.01 fW
-112 dBm6.31 fW
-111 dBm7.94 fWS6
-110 dBm10.00 fW
-109 dBm12.59 fWS3
-108 dBm15.85 fW
-107 dBm19.95 fW
-106 dBm25.12 fW
-105 dBm31.62 fWs7
-104 dBm39.81 fW
-103 dBm50.12 fWS4
-102 dBm63.10 fW
-101 dBm79.43 fW
-100 dBm100.00 fW
-99 dBm125.89 fWS8
-98 dBm158.49 fW
-97 dBm199.53 fWS5
-96 dBm251.19 fW
-95 dBm316.23 fW
-94 dBm398.11 fW
-93 dBm501.19 fWS9
-92 dBm630.96 fW
-91 dBm794.33 fWS6
-90 dBm1.00 pW
-89 dBm1.26 pW
-88 dBm1.58 pW
-87 dBm2.00 pW
-86 dBm2.51 pW
-85 dBm3.16 pWs7
-84 dBm3.98 pW
-83 dBm5.01 pWS9 + 10 dB
-82 dBm6.31 pW
-81 dBm7.94 pW
-80 dBm10.00 pW
-79 dBm12.59 pWS8
-78 dBm15.85 pW
-77 dBm19.95 pW
-76 dBm25.12 pW
-75 dBm31.62 pW
-74 dBm39.81 pW
-73 dBm50.12 pWS9S9 + 20 dB
-72 dBm63.10 pW
-71 dBm79.43 pW
-70 dBm100.00 pW
-69 dBm125.89 pW
-68 dBm158.49 pW
-67 dBm199.53 pW
-66 dBm251.19 pW
-65 dBm316.23 pW
-64 dBm398.11 pW
-63 dBm501.19 pWS9 + 10 dBS9 + 30 dB
-62 dBm630.96 pW
-61 dBm794.33 pW
-60 dBm1.00 nW
-59 dBm1.26 nW
-58 dBm1.58 nW
-57 dBm2.00 nW
-56 dBm2.51 nW
-55 dBm3.16 nW
-54 dBm3.98 nW
-53 dBm5.01 nWS9 + 20 dBS9 + 40 dB
-52 dBm6.31 nW
-51 dBm7.94 nW
-50 dBm10.00 nW
-49 dBm12.59 nW
-48 dBm15.85 nW
-47 dBm19.95 nW
-46 dBm25.12 nW
-45 dBm31.62 nW
-44 dBm39.81 nW
-43 dBm50.12 nWS9 + 30 dB
-42 dBm63.10 nW
-41 dBm79.43 nW
-40 dBm100.00 nW
-39 dBm125.89 nW
-38 dBm158.49 nW
-37 dBm199.53 nW
-36 dBm251.19 nW
-35 dBm316.23 nW
-34 dBm398.11 nW
-33 dBm501.19 nWS9 + 40 dB
-32 dBm630.96 nW
-31 dBm794.33 nW
-30 dBm1.00 µW
-29 dBm1.26 µW
-28 dBm1.58 µW
-27 dBm2.00 µW
-26 dBm2.51 µW
-25 dBm3.16 µW
-24 dBm3.98 µW
-23 dBm5.01 µW
-22 dBm6.31 µW
-21 dBm7.94 µW
-20 dBm10.00 µW
-19 dBm12.59 µW
-18 dBm15.85 µW
-17 dBm19.95 µW
-16 dBm25.12 µW
-15 dBm31.62 µW
-14 dBm39.81 µW
-13 dBm50.12 µW
-12 dBm63.10 µW
-11 dBm79.43 µW
-10 dBm100.00 µW
-9 dBm125.89 µW
-8 dBm158.49 µW
-7 dBm199.53 µW
-6 dBm251.19 µW
-5 dBm316.23 µW
-4 dBm398.11 µW
-3 dBm501.19 µW
-2 dBm630.96 µW
-1 dBm794.33 µW
0 dBm1.00 mWMax safe input power on most test equipment
1 dBm1.26 mW
2 dBm1.58 mW
3 dBm2.00 mW
4 dBm2.51 mW
5 dBm3.16 mW
6 dBm3.98 mW
7 dBm5.01 mW
8 dBm6.31 mW
9 dBm7.94 mW
10 dBm10.00 mWMax peak input power SDR Play DX
11 dBm12.59 mW
12 dBm15.85 mW
13 dBm19.95 mW
14 dBm25.12 mW
15 dBm31.62 mW
16 dBm39.81 mW
17 dBm50.12 mW
18 dBm63.10 mW
19 dBm79.43 mW
20 dBm100.00 mW
21 dBm125.89 mW
22 dBm158.49 mW
23 dBm199.53 mW
24 dBm251.19 mW
25 dBm316.23 mW
26 dBm398.11 mW
27 dBm501.19 mWFRS max power channels 8-14
28 dBm630.96 mW
29 dBm794.33 mW
30 dBm1.00 W
31 dBm1.26 W
32 dBm1.58 W
33 dBm2.00 WFRS max power channels 1-7,15-22
34 dBm2.51 W
35 dBm3.16 W
36 dBm3.98 W
37 dBm5.01 WMax peak power most 2 meter and 70cm HT
38 dBm6.31 W
39 dBm7.94 W
40 dBm10.00 W
41 dBm12.59 W
42 dBm15.85 W
43 dBm19.95 W
44 dBm25.12 W
45 dBm31.62 WMax power most 70 cm FM mobile radios
46 dBm39.81 W
47 dBm50.12 WMax power most 2 meter FM mobile radios
48 dBm63.10 W
49 dBm79.43 W
50 dBm100.00 WPeak power on most ham radio HF base stations
51 dBm125.89 W
52 dBm158.49 W
53 dBm199.53 W
54 dBm251.19 W
55 dBm316.23 W
56 dBm398.11 W
57 dBm501.19 W
58 dBm630.96 W
59 dBm794.33 W
60 dBm1.00 kW
61 dBm1.26 kW
62 dBm1.58 kWAmateur Radio Legal Limit
63 dBm2.00 kW
64 dBm2.51 kW
65 dBm3.16 kW
66 dBm3.98 kW
67 dBm5.01 kW
68 dBm6.31 kW
69 dBm7.94 kW
70 dBm10.00 kW
71 dBm12.59 kW
72 dBm15.85 kW
73 dBm19.95 kWMax power input of a 100 amp service US house
74 dBm25.12 kW
75 dBm31.62 kW
76 dBm39.81 kWMax power input of a 200 amp service US house
77 dBm50.12 kWOutput power of KSL 1160 AM
78 dBm63.10 kW
79 dBm79.43 kW
80 dBm100.00 kWMax US Broadcast Radio Station Power
81 dBm125.89 kW
82 dBm158.49 kW
83 dBm199.53 kW
84 dBm251.19 kW
85 dBm316.23 kW
86 dBm398.11 kW
87 dBm501.19 kW
88 dBm630.96 kW
89 dBm794.33 kW
90 dBm1.00 MW
91 dBm1.26 MW
92 dBm1.58 MW
93 dBm2.00 MW
94 dBm2.51 MW
95 dBm3.16 MW
96 dBm3.98 MW
97 dBm5.01 MW
98 dBm6.31 MW
99 dBm7.94 MW
100 dBm10.00 MW
101 dBm12.59 MW
102 dBm15.85 MW
103 dBm19.95 MW
104 dBm25.12 MW
105 dBm31.62 MW
106 dBm39.81 MW
107 dBm50.12 MW
108 dBm63.10 MW
109 dBm79.43 MW
110 dBm100.00 MW
111 dBm125.89 MW
112 dBm158.49 MW
113 dBm199.53 MW
114 dBm251.19 MW
115 dBm316.23 MW
116 dBm398.11 MW
117 dBm501.19 MW
118 dBm630.96 MW
119 dBm794.33 MW
120 dBm1.00 GW
121 dBm1.26 GW
122 dBm1.58 GW
123 dBm2.00 GWOutput from Hoover Dam

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