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dBm to Milliwatts Converter

Convert decibel-milliwatts to milliwatt instantly. Formula, worked steps and a full reference table.

How to use it

  • Type the value in decibel-milliwatts — the result updates as you type.
  • Use Swap to flip the direction, or change either dropdown to convert between any two units.
  • Click the result to copy it. The URL updates too, so you can bookmark or share the exact conversion.

Examples

1 dBm1.258925412 mW
5 dBm3.16227766 mW
10 dBm10 mW
100 dBm10000000000 mW

One decibel-milliwatts equals 1.2589254 milliwatts (mW). To convert decibel-milliwattses to milliwatts, multiply by 1.2589254; to go back the other way, multiply by 0 instead.

The converter above does it as you type and shows the working underneath, so you can check the arithmetic rather than take the number on trust.

What decibel-milliwattses and milliwatts actually measure

Decibel-milliwatts (dBm) — dBm is power on a logarithmic scale referenced to one milliwatt, so 0 dBm is exactly 1 mW. Radio, Wi-Fi signal strength and fibre optics.

Milliwatt (mW) — A milliwatt is a thousandth of a watt. Laser pointers, radio transmit power and low-power electronics.

dBm to Milliwatts conversion table

The most common values, worked out in advance. Anything not listed can be typed straight into the converter.

dBmmW
1 dBm1.2589254 mW
2 dBm1.5848932 mW
5 dBm3.1622777 mW
10 dBm10 mW
25 dBm316.22777 mW
50 dBm100000 mW
100 dBm1.0000e+10 mW

How to convert decibel-milliwattses to milliwatts by hand

Multiply the number of decibel-milliwattses by 1.2589254.

For example, 25 dBm × 1.2589254 = 316.22777 mW.

Going the other way, divide by 1.2589254 — or multiply by 0, which is the same thing and easier to do in your head.

Everything runs in your browser

There is no server involved in the calculation. The numbers you type never leave your device, nothing is logged, and the page keeps working with no connection once it has loaded. That is not a marketing line — it is simply how the tool is built, because a calculation like this has no reason to touch a network.

Questions people ask

How many mW are in 1 dBm?

This conversion uses a nonlinear formula. For example, 1 dBm = 1.258925412 mW.

Is anything uploaded to a server?

No. The whole calculation happens in your browser. Nothing is sent anywhere, and the page keeps working offline once loaded.

Runs entirely in your browser. Nothing you type is uploaded, logged or shared.

Last updated 18 August 2026