KiCad "Labels are similar (lower/upper case difference only)"
KiCad electrical rule check (schematic) message: Labels are similar (lower/upper case difference only) (similar_labels in kicad-cli reports).
What it means
KiCad net names are case-sensitive, so "SDA" and "sda" are two separate nets. ERC warns because that is almost always a typo that leaves the signal split in two.
Common causes
- Inconsistent capitalisation across sheets.
- Labels typed by hand instead of copied.
How to fix it
- Rename the labels to one spelling.
- Use the Find and Replace dialog to fix every instance.
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Checked against KiCad 10's source and documentation. Last reviewed 2026-11-07.
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