dBm ↔ Watt Converter
Type into any field — dBm, dBW, milliwatts or watts — and the others update instantly. The everyday unit converter every RF and telecom engineer needs.
Decibel-milliwatts
Decibel-watts (dBm − 30)
Linear power
1 mW = 0 dBm
- W = 10^((dBm − 30) / 10)
- dBm = 10 × log₁₀(W) + 30
- dBW = dBm − 30
- mW = 10^(dBm / 10)
Common RF reference levels
| dBm | Watts | Context | |
|---|---|---|---|
| 60 dBm | 1000 W | 1 kW — high-power broadcast | |
| 49 dBm | 79.432823 W | ~80 W — high-power macro per sector | |
| 46 dBm | 39.810717 W | 40 W — macro sector (typical) | |
| 43 dBm | 19.952623 W | 20 W — gNB per sector (typical) | |
| 30 dBm | 1 W | 1 W — small cell / CPE | |
| 23 dBm | 0.199526 W | 200 mW — UE max (Power Class 3) | |
| 0 dBm | 0.001 W | 1 mW — reference | |
| -80 dBm | 1.0000e-11 W | 10 pW — good cell edge RSRP | |
| -100 dBm | 1.0000e-13 W | 0.1 pW — typical cell edge RSRP | |
| -120 dBm | 1.0000e-15 W | 1 fW — noise floor region |
Why RF engineers live in dB
RF power in a cellular network spans roughly 16 orders of magnitude — from the tens of watts a gNB radiates per sector down to the attowatts a UE sees at the edge of coverage. Working in linear watts would be impractical, so the industry uses the decibel. dBm is simply decibels referenced to 1 milliwatt; 0 dBm is 1 mW, +30 dBm is 1 W, and every 10 dB is another factor of ten. dBW is the same thing referenced to 1 watt, so dBW = dBm − 30.
Because path loss, antenna gains, cable losses and noise figures are all logarithmic, the link budget becomes pure addition in dB: EIRP = TxPower (dBm) + AntennaGain (dBi) − CableLoss (dB). A clean mental map between dBm and watts makes those sums meaningful.
Typical levels
A 5G macro site usually runs +43 to +49 dBm (20–80 W) per sector depending on MIMO configuration. A small cell is around +24 to +30 dBm (0.25–1 W). A UE in Power Class 3 transmits up to +23 dBm (200 mW). Good RSRP is anywhere above −95 dBm; cell edge is typically −110 to −120 dBm, which is a vanishing 10⁻¹⁵ W of received power.
Related tools
How to use this tool
- Type into any field. Enter a value in dBm, dBW, mW or W.
- Let the others update. The remaining three units recalculate instantly from your input.
- Read the result. Compare against the listed RF reference levels (e.g. 43 dBm ≈ 20 W, 23 dBm UE max) if you need a sanity check.
Frequently asked questions
- How do I convert dBm to watts?
- Use P(W) = 10^((dBm − 30) / 10). The −30 accounts for dBm being referenced to 1 milliwatt rather than 1 watt. For example 43 dBm = 10^((43 − 30)/10) ≈ 20 W, a typical small-cell or RRU output. Going the other way, dBm = 10 × log10(P in mW).
- Why is the dBm-to-watt conversion logarithmic?
- The decibel scale is logarithmic because RF power spans many orders of magnitude, from picowatts at a receiver to tens of watts at a transmitter. A log scale keeps those numbers manageable and turns multiplication of gains and losses into simple addition, which is why link budgets are done in dB.
- What is the difference between dBm and dBW?
- Both are absolute power in decibels, just with different references: dBm is relative to 1 mW and dBW is relative to 1 W. They differ by a fixed 30 dB, so dBW = dBm − 30. The tool shows dBm, dBW, mW and W together so you can read whichever your data sheet uses.
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