Serial Monitor Garbage Output
Arduino Microcontroller Board
Severity: MinorWhat Does This Error Mean?
Garbage in the Arduino Serial Monitor is almost always a baud rate mismatch. The baud rate in the Serial Monitor dropdown (bottom right) must exactly match the number in your sketch's Serial.begin() call.
Affected Models
- Arduino Uno
- Arduino Nano
- Arduino Mega 2560
- Arduino Leonardo
- Arduino Pro Mini
- Arduino clones
Common Causes
- Baud rate in Serial Monitor does not match Serial.begin() in the sketch
- Wrong line ending setting causing extra characters
- Data printed before Serial is ready (missing Serial.begin() call)
- Using Software Serial at a speed the hardware cannot sustain
- USB cable quality causing character corruption at high baud rates