dBW to Watts Calculator
Enter a power level in dBW and instantly get the equivalent in watts and dBm — the units used in radar engineering, satellite link budgets, and broadcast transmitter specs.
Logarithmic to linear
dBW compresses a million-to-one power range into a compact scale. This calculator reverses that compression and gives you the true linear wattage your equipment delivers.
Negative dBW is valid
Negative dBW simply means less than 1 watt — common for low-power devices and receivers. Enter the negative value as-is; the calculator handles it correctly.
What is dBW?
Decibels relative to one watt
dBW is a logarithmic unit of power measured relative to one watt. It is standard in radar, satellite communications, and broadcast engineering because it turns the enormous range of real-world power levels — from milliwatts to megawatts — into a manageable scale where every 10 dBW step represents a factor-of-ten change in power. Zero dBW equals exactly 1 watt; 30 dBW equals 1 kilowatt. Because the reference is 1 watt rather than 1 milliwatt, dBW values are always 30 less than the equivalent dBm value.
Enter your dBW value — positive or negative — to get watts and dBm side by side.
The conversion raises 10 to the power of dBW divided by 10, which gives watts directly. The dBm equivalent is found by adding 30 to the dBW value, because dBm and dBW share the same logarithmic scale but differ by the factor between 1 mW and 1 W (which is 1 000, or 30 dB).
P(W) = 10^(dBW ÷ 10) dBm = dBW + 30At 0 dBW, 10^(0/10) = 10^0 = 1 W exactly — the reference point built into the unit's definition. At 20 dBW, 10^(20/10) = 10^2 = 100 W, equivalent to a typical FM radio transmitter. At −30 dBW, 10^(−3) = 0.001 W = 1 mW, the same as 0 dBm.
The dBW scale becomes intuitive once you know a handful of reference points commonly encountered in professional RF work. A 100 W FM transmitter in a small city operates at 20 dBW; a 1 kW radar pulse or high-power regional transmitter sits at 30 dBW; a large satellite uplink earth station might output 47 dBW (50 kW). On the low end, a −30 dBW (1 mW) signal represents the kind of received power seen at a satellite terminal before amplification.
Every +10 dBW step multiplies power by ten; a +3 dBW increase roughly doubles it, and a −3 dBW decrease roughly halves it. The relationship dBm = dBW + 30 is exact and constant — it follows directly from the fact that 1 W = 1 000 mW, and log₁₀(1 000) = 3, so the offset is 10 × 3 = 30 dB. Knowing this lets you switch between the two scales instantly when reading datasheets or link-budget spreadsheets that mix the two units.
This calculator performs the mathematical conversion only.
Conversion is mathematical — real-world links are more complex
The formula converts dBW to watts exactly, but actual RF system performance depends on antenna gain, cable loss, path loss, receiver sensitivity, and regulatory power limits. Turning a dBW figure into field strength or received signal level also requires antenna gain and path loss, which this tool does not model. Always consult the relevant standard or a qualified RF engineer before making transmitter power decisions for licensed equipment.