1. What is dBm?

dBm (decibels relative to one milliwatt) is a unit of power measurement used in radio, microwave, and fiber optic networks. It expresses power in decibels relative to 1 milliwatt (mW).

2. Watts to dBm Conversion Formula

The conversion formula is:

Where:

• \( W \) — Power in watts
• 1000 — Conversion factor (1 watt = 1000 milliwatts)
• \( \log_{10} \) — Base-10 logarithm

Explanation: The formula converts watts to milliwatts (×1000) then calculates the logarithmic decibel value (10×log10).

3. Practical Applications

Details: dBm is commonly used in RF engineering, telecommunications, and network design to express power levels in a logarithmic scale that better represents signal strength variations.

4. Using the Calculator

Tips: Enter power in watts (positive value). The calculator handles values from picowatts (enter as 0.000000001 W) to kilowatts.

5. Frequently Asked Questions (FAQ)

Q1: Why use dBm instead of watts?
A: dBm provides a logarithmic scale that makes it easier to work with very large and very small power values common in RF systems.

Q2: What are typical dBm values in wireless networks?
A: WiFi signals typically range from -30 dBm (very strong) to -90 dBm (very weak). Cellular signals range from -50 dBm to -120 dBm.

Q3: How does dBm relate to dB?
A: dBm is absolute power (relative to 1 mW), while dB is a relative measure between two power levels.

Q4: What's the dBm value for 1 watt?
A: 1 W = 1000 mW = 30 dBm (since 10×log10(1000) = 30).

Q5: Can dBm be negative?
A: Yes, negative dBm values represent power levels less than 1 milliwatt (e.g., -30 dBm = 0.001 mW = 1 μW).