Tax Return Calculator Australia
Estimate Your 2025-26 Refund — or Bill

Refund = total tax withheld (on your income statement in myGov) − the tax assessed on your taxable income. Assessed tax is income tax at resident rates, less offsets like the low income tax offset, plus the Medicare levy, any Medicare levy surcharge and any compulsory HELP repayment.

If it's negative, you owe the ATO.

Common reasons: a second job where the tax-free threshold was claimed twice; a HELP debt your employer wasn't told about; investment, rental or side-business income with no tax withheld; the Medicare levy surcharge because you had no private hospital cover; or large deductions last year that you don't have this year.

Your marginal rate plus Medicare levy (and HELP, since deductions reduce repayment income too). At $83,500 of taxable income, $1,000 of deductions saves $320.

Deductions need a record and must relate to earning your income.

The ATO says most returns lodged online are processed within 2 weeks. Returns can be lodged from 1 July; if you lodge yourself, the deadline for 2025-26 is 31 October 2026 (later through a registered tax agent).

It assumes a single Australian resident for the full year. It doesn't model family Medicare levy thresholds, the private health insurance rebate adjustment, the seniors and pensioners tax offset, foreign income, capital gains discounts, or franking credits.

MLS and HELP use taxable income, which is close to (but not exactly) the income tests the ATO applies.