dBm and watts
Calculate, convert and check circuit values in your browser.
Inputs
Results
- dBm
- 0 dBm
- Power
- 0.001 W
Formula and assumptions
P(W) = 10^(dBm/10)/1000; dBm = 10 log₁₀(1000 P(W))
Questions, examples and engineering limits
Convert dBm and watts, including negative dBm. See 0 dBm and 30 dBm examples and learn when impedance is needed for voltage conversion.
Content updated:
How is dBm to Watts Calculator: RF Power Conversion calculated?
Use P(W) = 10^(dBm/10)/1000. Convert dBm and watts, including negative dBm. See 0 dBm and 30 dBm examples and learn when impedance is needed for voltage conversion.
Sources: helpfiles.keysight.com [1]
How do I calculate this example: 30 dBm?
1 W. This is a calculated example under the model stated above; it is not a measured component specification.
Which units does dBm to Watts Calculator: RF Power Conversion use?
dBm, W, mW, µW. Convert prefixes before substituting values; keep the input and output units attached to every number.
Sources: helpfiles.keysight.com [1]
Are dB and dBm the same?
dB is a ratio; dBm is absolute power relative to 1 mW. A 3 dB gain approximately doubles power.
Sources: helpfiles.keysight.com [1]
Does negative dBm mean negative power?
No. −30 dBm = 1 µW, a positive power below the 1 mW reference.
Sources: helpfiles.keysight.com [1]
Can I convert dBm directly to V?
For a resistive load use Vrms = √(PR). At 0 dBm into 50 Ω, Vrms ≈ 0.2236 V; a different resistance changes voltage.
Sources: helpfiles.keysight.com [1]
Answers use the stated model and units. Examples are calculated values, not measurements or component ratings.