How to change language in Arduino IDE?

You can change the Arduino IDE interface language in Preferences/Settings (and then restart), or by editing the preferences.txt file.

Method 1: Change it inside Arduino IDE (recommended)

1. Open Arduino IDE

2. Open Preferences/Settings:

   • Windows / Linux: File → Preferences

   • macOS: Arduino IDE → Settings

3. In the Language option, pick your desired language

4. Click OK

5. Restart Arduino IDE for it to apply

macOS note: closing windows doesn’t always quit the app—use Quit from the Dock/menu to fully restart.

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Method 2: Force it by editing preferences.txt

1. Close Arduino IDE

2. Open the Arduino15 folder (paths below)

3. Open preferences.txt

4. Find the line: editor.languages.current

5. Set it, for example: editor.languages.current=en

6. Save the file and reopen Arduino IDE

Arduino15 folder locations

• Windows (standard install): C:\Users\{username}\AppData\Local\Arduino15
  (Windows Store install uses ArduinoData in Documents)

• macOS: /Users/{username}/Library/Arduino15

• Linux: /home/{username}/.arduino15

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Small caveat

Some messages in the Output panel come from third-party tools (compiler/uploader) and may stay in English even after you change IDE language.