Can I solve for different variables?

Yes! This calculator supports reverse solving. You can solve for: Power (watts), Power (milliwatts), Power (kilowatts), Power (dBm), Power (dBW).

What units can I use?

This calculator supports multiple unit systems. Select your preferred units from the dropdown menus next to each input field.

dBm to Watts Calculator

Convert radio power levels between dBm, dBW, watts, milliwatts, and kilowatts.

Formula shown4 inputs definedFree, no sign-up

Quick Summary

Use this when you need:

Translate RF link budgets between watts and dBm
Check whether an amplifier rating in dBW matches the wattage spec
Convert small wireless sensor power draw into milliwatts

You’ll need:Power (milliwatts), Power (kilowatts), Power (dBm), Power (dBW)

You’ll get:Power (watts)

How this is calculated

Formula:

power_watts = 10 ** ((power_dbm - 30) / 10); power_dbm = 10 * log10(power_watts) + 30

In plain language:

We convert between logarithmic dBm/dBW and linear watts by applying the standard 10*log10 relationship referenced to one milliwatt.

The formula is always visible so you can verify the math and explain your numbers to anyone who asks.

What these terms mean

Power (watts)

Power (watts) used in the calculation.

Power (milliwatts)

Power (milliwatts) used in the calculation.

Power (kilowatts)

Power (kilowatts) used in the calculation.

Power (dBm)

Power (dBm) used in the calculation.

Power (dBW)

Power (dBW) used in the calculation.

When to use this calculator

Translate RF link budgets between watts and dBm
Check whether an amplifier rating in dBW matches the wattage spec
Convert small wireless sensor power draw into milliwatts

Last updated: November 18, 2025

dBm to watts explained

RF engineers swap between logarithmic power (dBm) and linear watts whenever they read antenna charts, set up attenuators, or budget link margins. The dBm to Watts Calculator applies the industry-standard relation so you can move between milliwatts, watts, and dBm without breaking flow.

How the conversion works

The decibel-milliwatt definition fixes 0 dBm at 1 milliwatt. Converting either direction uses a single exponential or logarithm:

P_{\text{W}} = 10^{\frac{P_{\text{dBm}} - 30}{10}} \qquad P_{\text{dBm}} = 10 \log_{10}\left(P_{\text{W}} \times 1000\right)

Because the calculator keeps full precision, you can chain tiny RF values (micro-watts) and high-power amplifiers without losing resolution.

Units and conversions

Unit	Symbol	Relation
dBm	dBm	Logarithmic power referenced to 1 mW
MilliWatt	mW	$1\,\text{mW} = 0\,\text{dBm}$
Watt	W	$1\,\text{W} = 30\,\text{dBm}$
dBW	dBW	$P_{\text{dBW}} = P_{\text{dBm}} - 30$

Worked examples

Amplifier output stage
A driver spec calls for 17 dBm. Convert to watts to size a coupler.

P_{\text{W}} = 10^{(17-30)/10} = 0.0501\,\text{W}

Result: about 50 mW.

Reverse calculation from linear power
You measured 2.5 W at the coupler; convert to dBm for your link budget spreadsheet.

P_{\text{dBm}} = 10 \log_{10}(2.5 \times 1000) \approx 33.98\,\text{dBm}

Result: log 34 dBm.

Tips and pitfalls

These formulas assume power referenced to 1 mW into any impedance; if you work strictly in 50 Ω systems, convert voltages to watts before applying the dBm math.
Remember that +3 dB doubles power and −3 dB halves it—handy for quick mental checks.
Use dBW when comparing satellite uplinks (referenced to 1 W) but keep dBm for most lab instruments and small-signal work.
Keep calculations in linear watts when summing multiple sources, then convert the grand total back to dBm; adding dBm values directly is incorrect.

References and further reading

Frequently Asked Questions

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Calculator info

Version:: v1.0.0
Sensitivity:: low

Last updated: November 18, 2025

dBm to watts explained

How the conversion works

The decibel-milliwatt definition fixes 0 dBm at 1 milliwatt. Converting either direction uses a single exponential or logarithm:

P_{\text{W}} = 10^{\frac{P_{\text{dBm}} - 30}{10}} \qquad P_{\text{dBm}} = 10 \log_{10}\left(P_{\text{W}} \times 1000\right)

Because the calculator keeps full precision, you can chain tiny RF values (micro-watts) and high-power amplifiers without losing resolution.

Units and conversions

Unit	Symbol	Relation
dBm	dBm	Logarithmic power referenced to 1 mW
MilliWatt	mW	$1\,\text{mW} = 0\,\text{dBm}$
Watt	W	$1\,\text{W} = 30\,\text{dBm}$
dBW	dBW	$P_{\text{dBW}} = P_{\text{dBm}} - 30$

Worked examples

Amplifier output stage
A driver spec calls for 17 dBm. Convert to watts to size a coupler.

P_{\text{W}} = 10^{(17-30)/10} = 0.0501\,\text{W}

Result: about 50 mW.

Reverse calculation from linear power
You measured 2.5 W at the coupler; convert to dBm for your link budget spreadsheet.

P_{\text{dBm}} = 10 \log_{10}(2.5 \times 1000) \approx 33.98\,\text{dBm}

Result: log 34 dBm.

Tips and pitfalls

These formulas assume power referenced to 1 mW into any impedance; if you work strictly in 50 Ω systems, convert voltages to watts before applying the dBm math.
Remember that +3 dB doubles power and −3 dB halves it—handy for quick mental checks.
Use dBW when comparing satellite uplinks (referenced to 1 W) but keep dBm for most lab instruments and small-signal work.
Keep calculations in linear watts when summing multiple sources, then convert the grand total back to dBm; adding dBm values directly is incorrect.

Quick Summary

Calculator Tool

How this is calculated

What these terms mean

Power (watts)

Power (milliwatts)

Power (kilowatts)

Power (dBm)

Power (dBW)

When to use this calculator

dBm to watts explained

How the conversion works

Units and conversions

Worked examples

Tips and pitfalls

References and further reading

Frequently Asked Questions

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Calculator info

dBm to watts explained

How the conversion works

Units and conversions

Worked examples

Tips and pitfalls

References and further reading

Frequently Asked Questions

Related Calculators

Acreage Calculator

Acres to Hectares Converter

Acres to Square Feet Converter

Angle Conversion Calculator

Angstrom to nm converter

Area Converter

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Found an error?

Calculator info