---
title: "dB ↔ Linear Conversion calculator — AperiOptic"
description: "Convert between optical dB / dBm and linear ratios or power. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/db-linear-conversion"
---

# dB ↔ Linear Conversion calculator

Convert between optical dB / dBm and linear ratios or power.

Category: [Photonics](https://aperioptic.com/calculators)

Formula: `dB = 10·log₁₀(P/Pref)`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Loss/Gain | `dB` | dB | 3 |
| Power | `dBm` | dBm | 10 |

## Result with the default inputs

- Linear ratio: 1.9953×
- Power: 10 mW

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/db-linear-conversion?dB=3`](https://aperioptic.com/calculators/db-linear-conversion?dB=3). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Decibel](https://en.wikipedia.org/wiki/Decibel)

[All optics calculators](https://aperioptic.com/calculators)

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The interactive page: https://aperioptic.com/calculators/db-linear-conversion (AperiOptic runs in the browser; free, no account). Every page of the site as Markdown: https://aperioptic.com/llms.txt