Back Pay Calculator
If you've been paid the wrong hourly rate, back pay is straightforward arithmetic: the rate gap, times the hours affected, times how long it went on — plus superannuation on top. This calculator does that sum with every step shown. The harder cases (missed penalty rates, missing allowances) can't be reduced to one multiplication, and we're upfront below about where this estimate stops and a payslip-by-payslip check begins.
Quick Facts
- Formula
- Rate gap × hours/week × weeks
- Super on top
- 12% of underpaid wages
- Claim window
- Up to 6 years back
- Interest
- Courts can add interest on top
- Asking is protected
- A workplace right under the FW Act
- Evidence
- Free payslip check below
Tools & Resources
-
SCHADS AI Assistant
Get instant answers to award questions.
-
Timesheet Validator
Check timesheets for compliance.
-
Free Payslip Check
For workers: compare your payslip to the award minimums.
Calculate Your Back Pay
Default: SACS Level 2.1 from 1 Jul 2026
Claims reach back up to 6 years (312 weeks)
| Underpaid wages (/hr gap × hrs × weeks) | |
| Superannuation on the shortfall (12%) |
A gross (before tax) estimate for one flat rate gap — it doesn't price missed penalty rates, allowances or overtime, which usually add to the total. General information only, not legal or financial advice.
How Back Pay Is Calculated
For a flat rate gap, the formula is exactly what the calculator shows:
(correct hourly rate − paid hourly rate) × hours per week affected × weeks affected, plus 12% superannuation on the underpaid wages — because super was owed on the money you should have received. Courts and the Fair Work Ombudsman can add interest on top, and the calculation runs per pay period at the rate that applied at the time, so a gap that straddles a 1 July increase is calculated in two segments.
What a flat formula genuinely cannot price:
- Missed penalty rates — if your Sundays were paid at the weekday rate, the gap only applies to Sunday hours, at the penalty-rate difference. That needs your actual rosters.
- Missing allowances — sleepovers ($62.87/night), broken shifts ($21.81), vehicle kilometres ($1.01/km) are flat amounts per event, so the back pay is the count of events, not an hourly gap.
- Overtime and minimum engagements — both depend on when and how long each shift ran.
That per-shift arithmetic is exactly what underpayment usually looks like in care work — which is why the estimate above is a floor, not a ceiling.
Finding Your Correct Rate
The calculator is only as good as the "should have been paid" number. That rate comes from your award and classification, not from job ads or colleagues:
- Disability, community and home-care workers (SCHADS Award): our current rate tables list every level and pay point at the 1 July 2026 rates, and the levels guide explains which classification your duties match.
- Everyone else: the Fair Work Ombudsman's P.A.C.T. calculator covers every modern award and is the reference figure regulators themselves use.
- Casuals: remember the 25% loading belongs in your correct rate.
From Estimate to Evidence
An estimate opens the conversation; payslips settle it. If you work under the SCHADS Award, upload a payslip to our free payslip check and it compares every line — base rate, weekend rates, sleepover and broken-shift allowances, kilometres — against the current Fair Work minimums, and tells you with dollar figures which lines are below the minimum. That's the specific, dated evidence that turns "I think I'm underpaid" into a question your employer has to answer properly — and if it goes further, the Fair Work Ombudsman takes complaints free of charge, with claims reaching back up to 6 years.
Common Questions
Frequently Asked Questions
- How do I calculate my back pay?
- For a wrong hourly rate: (correct rate − paid rate) × hours per week affected × weeks it went on, plus 12% superannuation on the underpaid wages. Use the rate that applied at the time of each pay period — award minimums change every 1 July. Missed penalty rates and allowances are calculated per shift or per event instead, which usually adds to the total.
- How far back can back pay claims go in Australia?
- Up to 6 years from each underpayment under the Fair Work Act. A payroll error that ran for years is still recoverable for the most recent six — and courts can add interest on top of the principal.
- Is back pay taxed?
- Yes — back pay is taxed as ordinary income when you receive it. Where a lump sum covers earlier income years, the ATO's lump sum in arrears tax offset can reduce the extra tax caused by receiving it all at once; check with the ATO or a tax agent for your situation.
- Does my employer owe superannuation on back pay?
- Generally yes. Underpaid wages mean super was under-contributed on the same amounts, currently at 12%. Super shortfalls are handled through the ATO's superannuation guarantee charge process, which can add interest and administrative charges on top.
Automate SCHADS Compliance
Don't risk underpayments. CrossVault's AI engine validates every timesheet against the specific rules of the SCHADS Award.