RF Unit Converter

What this calculator does

RF and wireless signal power is almost always expressed in dBm (decibels relative to 1 milliwatt) rather than plain watts, because it compresses a huge dynamic range into small, easy-to-add numbers. This tool converts between dBm and milliwatts/watts.

The formulas

The standard relationship is P(dBm) = 10 × log10(P(mW)) and its inverse, P(mW) = 10^(dBm/10). Watts is simply milliwatts divided by 1000.

This logarithmic scale is why, for example, +3dBm is roughly double the power of 0dBm, and every additional 10dBm represents a 10× increase in power — a useful shortcut when comparing RF transmitter or receiver specs.