Convert milliwatts to dBW, dBm, watts, microwatts, kW, and MW, or find power loss in dB from transmitted and received power levels.
mW To dBW Formula
The formula to convert milliwatts (mW) to decibel-watts (dBW):
Inverse formula (dBW to mW):
- dBW is power expressed in decibels relative to 1 watt.
- mW is power in milliwatts (1 W = 1000 mW).
- dBW = dBm – 30 (exact: 1 W = 1000 mW, and 10 x log10(1000) = 30 dB).
Each 10x increase in milliwatts adds exactly 10 dBW. Doubling power adds 3.01 dBW.
| Milliwatts (mW) | dBW | dBm |
|---|---|---|
| 0.001 | -60.000 | -30.000 |
| 0.005 | -53.010 | -23.010 |
| 0.01 | -50.000 | -20.000 |
| 0.05 | -43.010 | -13.010 |
| 0.1 | -40.000 | -10.000 |
| 0.2 | -36.990 | -6.990 |
| 0.5 | -33.010 | -3.010 |
| 1 | -30.000 | 0.000 |
| 1.5 | -28.239 | 1.761 |
| 2 | -26.990 | 3.010 |
| 3 | -25.229 | 4.771 |
| 5 | -23.010 | 6.990 |
| 10 | -20.000 | 10.000 |
| 20 | -16.990 | 13.010 |
| 50 | -13.010 | 16.990 |
| 100 | -10.000 | 20.000 |
| 200 | -6.990 | 23.010 |
| 500 | -3.010 | 26.990 |
| 1,000 | 0.000 | 30.000 |
| 2,000 | 3.010 | 33.010 |
| 10,000 | 10.000 | 40.000 |
| 100,000 | 20.000 | 50.000 |
| dBW = 10 x log10(P[W]); dBm = dBW + 30. Anchor points: 1 mW = -30 dBW = 0 dBm; 1,000 mW = 0 dBW = 30 dBm. | ||
Real-World Power Reference
| Source / Technology | Reference Power | dBW |
|---|---|---|
| GPS L1 C/A (ICD reference minimum) | ~1.41 × 10⁻¹³ mW (~1.41 × 10⁻¹⁶ W) | -158.5 |
| Bluetooth LE (typical TX) | 1 mW | -30 |
| Bluetooth Classic Class 2 (maximum) | 2.5 mW | -26 |
| Bluetooth Classic Class 1 (maximum) | 100 mW | -10 |
| WiFi router (2.4 GHz, typical) | 100 mW | -10 |
| LTE smartphone (max uplink, 4G) | 200 mW | -7 |
| Wi-Fi (US 5.725–5.850 GHz, max conducted power) | 1,000 mW | 0 |
| GSM handset (900 MHz, Class 4 nominal max) | 2,000 mW | +3 |
| 4G LTE base station (per carrier) | 20,000 mW | +13 |
| FM broadcast transmitter (50 kW) | 50,000,000 mW | +47 |
| Direct broadcast satellite EIRP (Ku-band) | ~100,000,000 mW | ~+50 |
| EIRP values include antenna gain. GPS L1 C/A minimum uses the ICD reference antenna (3 dBi, linearly polarized, near ground) with satellite elevation above 5 degrees; actual received power varies. Wi-Fi limits are subject to FCC spectral-density and antenna-gain rules and vary by subband and device category. Other representative values are examples, not universal device specifications. | ||
What is dBW?
dBW (decibel-watt) measures power on a logarithmic scale referenced to 1 watt. In RF engineering, gains and losses through a signal chain add and subtract in dB rather than requiring multiplication of large power ratios. A satellite with an EIRP of 52 dBW (~158,000 W effective) and a ground receiver sensitive to -120 dBW (1 picowatt) spans a 172 dB link budget. In linear watts, those same values represent a ratio of 1.58 x 10^17, which makes the logarithmic scale convenient for link-budget calculations. dBW is the preferred unit for satellite EIRP, broadcast transmitter output, and FCC power limit specifications, while dBm dominates at receiver and low-power circuit levels.
