The dBW (decibel-watts) scale is used in radio, audio, and telecommunications engineering to express power levels relative to 1 watt — and converting between dBW and watts by hand requires working through exponents. Enter a dBW value or a Watts value and select your conversion direction to get the converted value, plus a dBm equivalent and milliwatts equivalent as secondary outputs.
Converted Value
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dBm Equivalent
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Milliwatts Equivalent
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dBW (decibel-watts) is a unit of power referenced to 1 watt, while dBm is referenced to 1 milliwatt. dBW = dBm - 30, so 0 dBW equals 30 dBm.
Use the formula: P(W) = 10^(P(dBW)/10). For example, 20 dBW = 10^(20/10) = 100 watts.
Use the formula: P(dBW) = 10 × log10(P(W)/1W). For example, 100 watts = 10 × log10(100) = 20 dBW.
0 dBW represents exactly 1 watt of power. This is the reference point for the dBW scale.
-30 dBW equals 0.001 watts or 1 milliwatt. This is a common reference point in RF calculations.
dBW makes it easier to work with very large or small power values, simplifies calculations involving gains and losses, and provides better resolution for small changes.
Common values range from -30 dBW (1 mW) for small signals to +60 dBW (1 MW) for high-power transmitters. Most RF applications use values between -10 to +50 dBW.
Yes, negative dBW values represent power levels less than 1 watt. For example, -10 dBW equals 0.1 watts or 100 milliwatts.