RF power level conversion between Watts, milliwatts, dBm, and dBW is fundamental to RF engineering, wireless systems, and signal analysis. dBm (decibels relative to 1 milliwatt) is the standard unit for expressing signal strength, transmitter output, and receiver sensitivity in radio frequency work.
Watts / Milliwatts to dBm
dBm to Watts
Common Power Level Reference
| dBm | Watts | mW | Typical Use |
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How to Use the RF Power to dBm Converter
This RF power converter converts between Watts, milliwatts, dBm, and dBW. Enter a power value in Watts or milliwatts to get the dBm equivalent, or enter a dBm value to convert back to linear power units.
dBm Formula
dBm = 10 × log10(P_mW) where P_mW is power in milliwatts. The reverse: P_mW = 10^(dBm/10). Key reference: 0 dBm = 1 mW. Every 10 dBm increase multiplies power by 10. Every 3 dBm doubles power.
Common Power Levels
Bluetooth Low Energy transmits at 0 dBm (1 mW). Typical WiFi routers use 17–20 dBm (50–100 mW). A 100W FM transmitter operates at 50 dBm. The received signal at your phone from a cell tower is typically -70 to -90 dBm. Understanding these levels helps diagnose link budget problems in RF system design.
dBm vs dBW
dBW references 1 Watt instead of 1 milliwatt. dBW = dBm − 30. Satellite engineers often use dBW since satellite EIRP values are in the range of 40–60 dBW (10kW–1MW equivalent). Most RF test equipment displays in dBm for easier comparison at typical signal levels.
Frequently Asked Questions
Is this Watts to dBm converter free?
Yes, completely free. Convert between any power units without any account or payment.
Is my data private?
All calculations run in your browser. No data is sent to any server.
What is dBm?
dBm is power measured in decibels relative to 1 milliwatt (0 dBm = 1 mW). The formula is dBm = 10 × log10(P_mW). It's a logarithmic scale: every 3 dBm doubles the power, and every 10 dBm multiplies power by 10. Widely used in RF, microwave, fiber optics, and audio engineering.
How do I convert Watts to dBm?
dBm = 10 × log10(P_W × 1000) = 10 × log10(P_mW). Key references: 1mW = 0 dBm, 10mW = 10 dBm, 100mW = 20 dBm, 1W = 30 dBm, 10W = 40 dBm, 100W = 50 dBm, 1kW = 60 dBm.
What is dBW?
dBW is power relative to 1 Watt. 0 dBW = 1W = 30 dBm. dBW = dBm - 30. Used in satellite communications and broadcasting where watt-level powers are common.
What is a typical WiFi transmit power in dBm?
WiFi routers typically transmit at 15–20 dBm (32–100 mW) in the US (FCC limits). USB WiFi adapters are usually 10–15 dBm. Received signal strength at a distance is much lower, typically -50 to -80 dBm (excellent to fair coverage).
What is a good received signal strength (RSSI)?
-30 dBm = excellent (very close to access point). -50 dBm = very good. -67 dBm = good (reliable stream). -70 dBm = acceptable (basic usage). -80 dBm = weak (may drop). -90 dBm = very weak (borderline connection). Mostly relevant for WiFi and cellular signals.