Enter a power value into the calculator to find its equivalent in decibel-watts (dBW). Supports mW, W, kW, and MW as input. The advanced tab converts between watts, dBW, and dBm simultaneously.
mW To dBW Formula
The formula to convert milliwatts (mW) to decibel-watts (dBW):
dBW = 10 * log10(mW / 1000)
Inverse formula (dBW to mW):
mW = 1000 * 10^(dBW / 10)
- 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 | Typical Power | dBW |
|---|---|---|
| GPS L1 received at antenna | ~10⁻¹³ mW (10⁻¹⁶ W) | -160 |
| Bluetooth LE (typical TX) | 1 mW | -30 |
| Bluetooth Classic Class 2 | 2.5 mW | -26 |
| Bluetooth Classic Class 1 | 100 mW | -10 |
| WiFi router (2.4 GHz, typical) | 100 mW | -10 |
| LTE smartphone (max uplink, 4G) | 200 mW | -7 |
| WiFi (5 GHz, max US unlicensed) | 1,000 mW | 0 |
| GSM handset (900 MHz, Class 1 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 figure is the minimum received signal at the antenna connector per GPS ICD specification. | ||
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 practical system design impossible without the logarithmic scale. 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.
