What power level does a receiver minimum discernible signal of -100 dBm represent?

Decibels relative to a milliwatt (dBm) is a logarithmic unit where 0 dBm equals 1 milliwatt. Every 10 dB decrease represents a division of power by 10, and every 30 dB decrease represents a division by 1,000. A simple way to calculate this is to step down from 0 dBm in 30 dB increments. So, -30 dBm is 1 microwatt, -60 dBm is 1 nanowatt, and -90 dBm is 1 picowatt. Since -100 dBm is exactly 10 dB less than -90 dBm, the power is one-tenth of a picowatt. Therefore, -100 dBm represents 0.1 picowatts.