Convert power between dBm, watt, milliwatt and kilowatt. Free tool for telecommunications, RF and electrical engineering.
dBm (decibel-milliwatt) is a logarithmic power unit that expresses a power level in decibels (dB) relative to a reference of 1 milliwatt (mW). Unlike the watt, which is a linear unit, dBm uses a logarithmic scale — each 10 dBm increase corresponds to 10 times more power, and each 3 dBm increase corresponds to roughly double. This makes dBm ideal for expressing very wide power ranges with compact numbers, common in telecommunications, radio frequency (RF), fiber optics, and antenna engineering. The conversion formula is: P(mW) = 10^(dBm/10), and therefore P(W) = 10^(dBm/10) / 1000. In the reverse direction, dBm = 10 × log₁₀(P(mW)). Thus, 0 dBm = 1 mW, 10 dBm = 10 mW, 20 dBm = 100 mW = 0.1 W, and 30 dBm = 1,000 mW = 1 W. These reference values are memorized by any RF engineer. This converter calculates between dBm, watt, milliwatt, and kilowatt, correctly handling the logarithmic relationship of dBm and the linear conversions between watt-based units. It is essential for telecommunications engineers configuring transmitters, RF technicians measuring antenna power, and optical network professionals interpreting equipment specifications in dBm.
dBm is decibel-milliwatt: a logarithmic power unit relative to 1 mW. 0 dBm = 1 mW.
P(W) = 10^(dBm/10) / 1000. Example: 30 dBm = 10³ / 1000 = 1 W.
20 dBm = 100 mW = 0.1 W.
Because it uses the decibel scale: each 10 dBm = 10× more power, each 3 dBm ≈ 2× more. This compacts wide power ranges.
Yes, completely free, with no registration and no usage limit.