Methodology
Every figure a OneCalculate calculator uses — a tax bracket, a levy rate, a repayment threshold — has to trace back to a named, official source. This page explains where those numbers come from, how often we check them, and what to do if you think one is wrong.
Where the numbers come from
We only use primary, official sources for Australian figures:
- Australian Taxation Office (ato.gov.au) for income tax, Medicare levy, GST and HECS-HELP repayment rates
- Fair Work Ombudsman (fairwork.gov.au) for casual loading, minimum wages and award-based penalty rates
- Study Assist (studyassist.gov.au) for study and training loan thresholds
- State and territory revenue offices for stamp duty and property-related figures
- Moneysmart (moneysmart.gov.au) for consumer finance definitions
- Australian Government Department of Health for standard drink and alcohol guidelines
Every calculator page links directly to the specific source page each figure came from, in the trust strip at the bottom of the article.
Current review status
Rates on this site are currently set for FY2026-27 (1 July 2026 – 30 June 2027) and were last reviewed on 18 August 2026.
| Rate | Source |
|---|---|
| Individual income tax brackets | ATO — tax rates, Australian residents |
| Medicare levy | ATO — Medicare levy |
| HECS-HELP repayment thresholds | ATO — study and training loan repayment |
| GST | ATO — how Australian GST works |
| Superannuation Guarantee | ATO — super guarantee percentage |
| Casual loading | Fair Work Ombudsman — casual employees |
| Public holiday penalty rates | Fair Work Ombudsman — public holiday penalty rates (award-specific, not a single national rate) |
| Standard drink definition | Department of Health — standard drinks guide |
Update calendar
Australian tax and pay rates change on 1 July each year. Every pay and tax calculator is reviewed in the lead-up to 1 July, and again whenever a mid-year change is announced (a Budget measure, an award variation, an indexed threshold). The "last updated" date and reviewer name on every calculator page reflect the most recent check, not just the publish date.
Before we publish loans, super or Centrelink calculators
Categories with higher stakes and more complex rules — loans, superannuation and Centrelink payments — get a paid review pass from an Australian accountant or registered tax agent before they publish, and that reviewer is credited by name on the page. We don't publish in these categories without that review.
Corrections
If you spot a rate that's out of date or a formula that doesn't match your situation, tell us viacontact. We fix confirmed errors promptly and update the "last updated" date when we do — we don't backdate or hide corrections.