what is the maximum you can claim for car expenses

The ATO gives you two doors: cents‑per‑kilometre or logbook.

Under cents‑per‑km, you can claim up to 5,000 business km per car per year at the ATO rate for that year—so the maximum is simply 5,000 × the rate. The logbook method has no fixed dollar cap, but you only claim your business‑use percentage of actual running costs (fuel, servicing, insurance, rego, interest/lease, depreciation). Depreciation and GST credits are limited by the car cost limit, and private trips—yes, including the commute—don’t count. You must pick one method per car per year and keep decent records, not heroic guesses. For exact rates and thresholds, consult the ATO or a tax professional before the taxman does.