Power conversion

dBm to Watts conversion

Convert dBm to watts (W). Formula: W = 10^((dBm−30)/10). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.

Instant result

Result

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Enter values to convert.

Inputs —

Mode —

Formula —

Formulas

Core equations used by this converter.

FormulaP(W) = 10^((dBm − 30) / 10)

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

How to use

Convert dBm → mW with 10^(dBm/10).

Divide by 1000 to get watts.

Or use the combined formula above.

Example conversions

Common values with formula and result.

30 dBm to watts

10^((30−30)/10) = 1 W

1 W

0 dBm to watts

0.001 × 10^0 = 0.001 W = 1 mW

1 mW

40 dBm to watts

10^((40−30)/10) = 10 W

10 W

20 dBm to watts

10^((20−30)/10) = 0.1 W = 100 mW

100 mW

dBm to Watts conversion specification

Version 1.3.1 · Engine tested · Internally reviewed · 2026-09-13

Calculation status

Engine tested 4 published cases
Supplemental domain review Internal · Pass · electrical-engineer · 2026-09-13
Calculation version 1.3.1

Review policy · Reviewed by CalculatorX electrical review (electrical-engineer)

Definition: **dBm** — dB relative to 1 mW. **Watt (W)** — SI power; 1 W = 1000 mW = 30 dBm.
What it calculates: Convert dBm to watts (W). Formula: W = 10^((dBm−30)/10). 30 dBm = 1 W. Examples and chart.
Inputs: Values required by the selected conversion mode
Outputs: Converted result in the target unit or format
Formula: P(W) = 10^((dBm − 30) / 10)
dBm to watts conversion table: dBm Watts (W)
0 0.001
10 0.01
20 0.1
30 1
33 ≈2
40 10
50 100
60 1,000
Assumptions: Conversion runs locally in the browser; values are not uploaded.
Uses the formulas documented on this page.
Units: Formula
Boundary conditions: Empty or invalid input yields no valid result.
Out-of-range values may be rejected by the tool runtime.
Example: 30 dBm to watts → 1 W
Validation cases: 30 dBm to watts → 1 W
0 dBm to watts → 1 mW
40 dBm to watts → 10 W
20 dBm to watts → 100 mW
Sources: CalculatorX converter runtime
Standard unit / encoding definitions where applicable
Last reviewed: 2026-09-13
Calculation version: 1.3.1

dBm	Watts (W)
0	0.001
10	0.01
20	0.1
30	1
33	≈2
40	10
50	100
60	1,000

Background

Interpretation and common distinctions.

Lightweight SEO converter sibling. Canonical engineering / Agent calculator: /calc/electric/dbm-watt.

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

Agent / API notes

Capability id: units.rf.dbm_watts · tool id: dbm-watt · pin 1.3.1. Canonical page: /calc/electric/dbm-watt. This /convert/power/dbm-to-watt sibling is the lightweight SEO converter.

PF-style hard errors: VALUE_MUST_BE_POSITIVE when converting from watts/mW ≤ 0.

Frequently asked questions

Key distinctions behind the conversion.

How do you convert using dBm to Watts conversion?

Use P(W) = 10^((dBm − 30) / 10). Example: 30 dBm to watts → 1 W.

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.