Google's SWE levels and approximate total compensation (TC) ranges:
L3 (Entry): Base \130$170$180$28002$ years.
L4 (Mid): Base \155$195$250$40025$ years.
L5 (Senior): Base \185$230$350$550510$ years. This is the career level where most engineers stay.
L6 (Staff): Base \210$260$500$800$K+. Requires demonstrated broad impact.