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 absolute power in decibels relative to 1 milliwatt (mW).

2. Conversion Formula

The calculator uses the following formula:

Where:

• \( W \) — Power in watts
• 1000 — Conversion factor (1 watt = 1000 milliwatts)
• log10 — Base-10 logarithm

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

3. Practical Applications

Details: dBm measurements are essential in RF engineering, telecommunications, and network design for power level specifications and signal strength measurements.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What does 0 dBm mean?
A: 0 dBm equals exactly 1 milliwatt (0.001 W). It's the reference level for dBm measurements.

Q2: What's the difference between dB and dBm?
A: dB is relative (a ratio), while dBm is absolute (referenced to 1 mW). dBm specifies actual power level.

Q3: What are typical dBm values in wireless networks?
A: WiFi signals typically range from -30 dBm (excellent) to -90 dBm (poor). Cellular signals range from -50 dBm to -120 dBm.

Q4: How does dBm scale with power?
A: +3 dBm ≈ 2× power, +10 dBm = 10× power. -3 dBm ≈ ½ power, -10 dBm = 1/10th power.

Q5: Can dBm be negative?
A: Yes, negative dBm values indicate power levels less than 1 milliwatt (e.g., -30 dBm = 0.000001 W).