dBm (decibel-milliwatts) is a logarithmic unit used to express radio frequency and optical signal power levels — common in wireless, audio, and networking applications. Enter your Power (dBm) value into the dBm to Watts Calculator to convert it to Watts and Milliwatts. Also try the use the RF Power Conversion Calculator.
Power (Watts)
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Power (Milliwatts)
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A dBm to watts conversion calculator is a tool that converts power measurements from decibel-milliwatts (dBm) to watts (W) and milliwatts (mW). It's commonly used in RF engineering and telecommunications to work with power levels. See also our calculate kW to VA Apparent Power.
To convert dBm to watts, use the formula: P(W) = 10^((P(dBm) - 30) / 10). For example, 10 dBm = 10^((10-30)/10) = 0.01 watts or 10 milliwatts.
dBm is a logarithmic unit expressing power relative to 1 milliwatt, while watts is a linear unit of power. dBm makes it easier to work with very small or very large power values in telecommunications and RF applications.
dBm is preferred because it compresses a wide range of power values into a manageable scale. It also makes calculations easier when dealing with gains and losses, as you can simply add or subtract dB values instead of multiplying or dividing. You might also find our Amps to kW Calculator useful.
0 dBm equals exactly 1 milliwatt (0.001 watts). This is the reference point for the dBm scale, as dBm measures power relative to 1 milliwatt.
The conversion is mathematically exact when using the proper formula. Our calculator provides high precision results with multiple decimal places to ensure accuracy for engineering applications.
Yes, negative dBm values represent power levels less than 1 milliwatt. For example, -10 dBm equals 0.1 milliwatts or 0.0001 watts. Our calculator handles the full range of dBm values.
Common values include: cell phone transmit power (23-27 dBm), WiFi access points (15-20 dBm), Bluetooth devices (0-4 dBm), and receiver sensitivity levels (-80 to -100 dBm).