Power conversion

dBm Converter

Convert between dBm, milliwatts, and watts. Formulas: mW = 10^(dBm/10), dBm = 10×log10(mW). Free online tool — no sign-up. Runs locally in your browser.

Instant result

Result

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Inputs —

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Formula —

Formulas

Core equations used by this converter.

dBm ↔ milliwattsP(mW) = 10^(dBm / 10) dBm = 10 × log10(P_mW)

dBm ↔ wattsP(W) = 10^((dBm − 30) / 10) dBm = 10 × log10(P_W) + 30

iFollow the formulas shown. Calculation runs locally in your browser.

How to use

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Convert and read the result

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Example conversions

Common values with formula and result.

13 dBm → mW

10^(13/10) ≈ 20 mW

0.5 W → dBm

10 × log10(0.5) + 30 ≈ 27 dBm

Steps (dBm → mW)

10^(13/10) ≈ 20 mW

dBm converter specification

Version 1.1.0 · Engine tested

Calculation status

Engine tested 3 published cases
Named expert review Not performed
Calculation version 1.1.0

Review policy

Definition: **dBm** (decibel-milliwatts) expresses power on a logarithmic scale relative to **1 milliwatt**:
What it calculates: Convert between dBm, milliwatts, and watts. Formulas: mW = 10^(dBm/10), dBm = 10×log10(mW). Reference chart and links.
Inputs: Values required by the selected conversion mode
Outputs: Converted result in the target unit or format
Formula: P(mW) = 10^(dBm / 10) dBm = 10 × log10(P_mW) · P(W) = 10^((dBm − 30) / 10) dBm = 10 × log10(P_W) + 30
dbm converter chart: dBm mW W
−20 0.01 0.00001
−10 0.1 0.0001
0 1 0.001
10 10 0.01
20 100 0.1
30 1,000 1
40 10,000 10
Assumptions: Conversion runs locally in the browser; values are not uploaded.
Uses the formulas documented on this page.
Units: dBm ↔ milliwatts
dBm ↔ watts
Boundary conditions: Empty or invalid input yields no valid result.
Out-of-range values may be rejected by the tool runtime.
Example: 13 dBm → mW → 10^(13/10) ≈ 20 mW
Validation cases: 13 dBm → mW → 10^(13/10) ≈ 20 mW
0.5 W → dBm → 10 × log10(0.5) + 30 ≈ 27 dBm
Steps (dBm → mW) → 10^(13/10) ≈ 20 mW
Sources: CalculatorX converter runtime
Standard unit / encoding definitions where applicable
Calculation version: 1.1.0

dBm	mW	W
−20	0.01	0.00001
−10	0.1	0.0001
0	1	0.001
10	10	0.01
20	100	0.1
30	1,000	1
40	10,000	10

Background

Interpretation and common distinctions.

Use the converter tabs to switch direction when available. Results for dBm Converter update locally in your browser.

Frequently asked questions

Key distinctions behind the conversion.

How do you convert using dBm Converter?

Use P(mW) = 10^(dBm / 10) dBm = 10 × log10(P_mW). Example: 13 dBm → mW → 10^(13/10) ≈ 20 mW.

Can I switch direction?

Open the related reverse converter listed under Related tools.

Does this run online or locally?

Calculation runs locally in your browser. Values are not uploaded.

How precise are the results?

Results follow the formulas on this page. Round to the precision your use case needs.