dBm to dBW Conversion

Formula

Description

dBm references power to 1 milliwatt, while dBW references power to 1 watt. Since 1 W = 1000 mW, the difference is exactly 30 dB. This conversion is trivial but essential when working with RF link budgets where some parameters are specified in dBm and others in dBW. Satellite communications typically use dBW (or dBW/m² for flux density), while terrestrial RF and cellular systems predominantly use dBm. A 0 dBm signal is 1 mW = −30 dBW, and a 0 dBW signal is 1 W = +30 dBm.

Variables

• dBW — Power in decibels relative to 1 watt
• dBm — Power in decibels relative to 1 milliwatt

Practical Notes

Common reference levels: 0 dBm = 1 mW = −30 dBW, 30 dBm = 1 W = 0 dBW, 40 dBm = 10 W = 10 dBW. Wi-Fi access points typically transmit at 20-23 dBm (100-200 mW). Cellular base stations transmit at 43-46 dBm (20-40 W). Satellite uplinks can be 50-60 dBW (100 kW − 1 MW EIRP).