Milliwatt to dBW Converter
Power · unit-converter
Convert Milliwatt to dBW with a fixed input and output unit, step-by-step formula line, and reference tables. Linear units use SI watt definitions; mechanical hp uses 550 ft·lbf/s; BTU/h uses the IT BTU; dBm/dBW are logarithmic relative to 1 mW and 1 W. The full Power Converter also includes PS/CV, TR, kVA/MVA, and ft·lb/s.
Calculator
From: Milliwatt (mw)
To: dBW (dbw)
About Milliwatt
One milliwatt is one thousandth of a watt. Common in RF, fiber optics, and low-power electronics.
About dBW
dBW is a logarithmic power level relative to 1 W: P(W) = 10^(dBW/10). RF, microwave, and antenna work often use dBW with dBm.
How to convert milliwatts to decibels relative to 1 w (dbw)
dBm/dBW are logarithmic power levels. P_W = 10^((dBm − 30) / 10), P_W = 10^(dBW / 10), and inverse mappings use 10 × log₁₀(·) with P_W > 0.
From Milliwatt, multiply by 0.001 W per mw to get watts, then apply the dBm formula (watts must be positive).
Examples
Example #1: Convert 10 mw to dbw
10 mw → -20 dbw
Example #2: Convert 30 mw to dbw
30 mw → -15.228787 dbw
Summary
To convert Milliwatt to dBW, multiply by watts per mw, then apply dBW: dBW = 10 × log₁₀(P_W), where P_W = value_mw × 0.001. Watts must be positive.
Relationship context
You are converting between SI / decimal power (watts and prefixes) (Milliwatts) and logarithmic RF levels (dBm) (Decibels relative to 1 W (dBW)). Log units (dBm/dBW) use base-10 definitions relative to 1 mW or 1 W; linear units map through watts first, then to or from the selected log unit. Only strictly positive power in watts maps to a real dB power value.
Conversion tables
| Milliwatt (mw) | dBW (dbw) |
|---|---|
| 0.1 | -40 |
| 1 | -30 |
| 2 | -26.9897 |
| 3 | -25.228787 |
| 4 | -23.9794 |
| 5 | -23.0103 |
| 6 | -22.218487 |
| 7 | -21.54902 |
| 8 | -20.9691 |
| 9 | -20.457575 |
| Milliwatt (mw) | dBW (dbw) |
|---|---|
| 10 | -20 |
| 20 | -16.9897 |
| 30 | -15.228787 |
| 40 | -13.9794 |
| 50 | -13.0103 |
| 60 | -12.218487 |
| 70 | -11.54902 |
| 80 | -10.9691 |
| 90 | -10.457575 |
| 100 | -10 |