Last updated: 30 January 2026

How PayByRoster Calculates Your Pay

A detailed, step-by-step breakdown of our calculation methodology. Technical enough for developers and accountants to verify accuracy, readable enough for everyone to understand.

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Calculation Flow

Roster Pattern

Gross Pay

Tax + Medicare + HECS

Net Pay

Calculation Overview

PayByRoster calculates your annual gross pay from your roster, then deducts income tax, Medicare Levy, and HECS (if applicable), and adds superannuation on top.

Our calculator follows the same methodology used by the Australian Taxation Office (ATO) for calculating income tax. The process involves six key steps:

Calculate Gross Income — From your roster pattern, hourly rate, shift penalties, and allowances
Apply Tax Brackets — Using the 2025-26 ATO resident tax rates
Add Medicare Levy — 2% of taxable income (with low-income exemptions)
Apply LITO — Low Income Tax Offset reduces tax for incomes under $66,667
Add HECS/HELP — Compulsory repayments if you have a study debt
Calculate Superannuation — 12% of ordinary time earnings

Step 1: Calculate Gross Income

Gross pay = (Base rate × Hours × Penalties) + Allowances, calculated for every working day in your roster over a full year.

Your gross income is calculated by applying your hourly rate across all working days in your roster pattern for a full financial year (1 July – 30 June).

The Formula

Annual Gross = Σ (Daily Hours × Base Rate × Day Multiplier × Shift Multiplier) + Allowances

Sum of daily pay across all working days in the year, plus daily allowances.

Components Explained

Component	Description	Example
Base Rate	Your standard hourly rate before penalties	$55.00/hour
Daily Hours	Hours worked per shift	12 hours
Day Multiplier	Weekend/public holiday loading	1.5× for Saturdays
Shift Multiplier	Night shift or other shift loadings	1.15× for night shift
Allowances	FIFO, living away, travel allowances per day	$50/day

Working Days Per Year: For an 8/6 roster (8 days on, 6 days off), you work approximately 209 days per year. We calculate the exact number by projecting your roster pattern across 365 days.

Step 2: Apply Tax Brackets (2025-26)

Income tax is calculated in slices. You pay 0% on the first $18,200, then increasing rates on each bracket above that.

Australia uses a progressive tax system. This means you don't pay a flat rate on all your income — instead, different portions of your income are taxed at different rates.

2025-26 Tax Brackets (Residents)

Taxable Income	Tax Rate	Tax Formula
$0 – $18,200	0%	Nil
$18,201 – $45,000	16%	16 cents for each $1 over $18,200
$45,001 – $135,000	30%	$4,288 + 30 cents for each $1 over $45,000
$135,001 – $190,000	37%	$31,288 + 37 cents for each $1 over $135,000
$190,001+	45%	$51,638 + 45 cents for each $1 over $190,000

Plain English Calculation

Income Tax = Base Amount + (Income − Threshold) × Rate

Where 'Base Amount' and 'Threshold' come from the bracket your income falls into.

Step 3: Add Medicare Levy

Most Australians pay 2% of their taxable income as the Medicare Levy. Low-income earners may pay less or nothing.

Medicare Levy = Taxable Income × 0.02

Standard rate for incomes above $27,222 (singles, 2025-26).

Low Income Thresholds (2025-26)

Income Range	Medicare Levy
Below $26,000	Nil (fully exempt)
$26,000 – $32,500	Reduced rate (phases in at 10% of excess over $26,000)
Above $32,500	Full 2%

Medicare Levy Surcharge: High earners ($93,000+ single) without private hospital cover may pay an additional 1.0–1.5% surcharge. PayByRoster does not currently include this in calculations.

Step 4: Apply LITO (Low Income Tax Offset)

LITO reduces your tax by up to $700 if you earn less than $66,667. It phases out between $37,500 and $66,667.

LITO Amounts (2025-26)

Taxable Income	LITO Amount
$0 – $37,500	$700 (full offset)
$37,501 – $45,000	$700 minus 5 cents for each $1 over $37,500
$45,001 – $66,667	$325 minus 1.5 cents for each $1 over $45,000
$66,668+	Nil

For income $45,001–$66,667: LITO = $325 − (Income − $45,000) × 0.015

LITO reduces to zero at $66,667.

Step 5: Calculate HECS/HELP Repayment

If you have a HECS/HELP study debt and earn above $54,435 (2025-26), a percentage of your income is withheld as a repayment.

HECS repayments are calculated on your Repayment Income (taxable income + any reportable fringe benefits + net investment losses). The repayment is a percentage of your total income, not just the amount over the threshold.

2025-26 HECS/HELP Repayment Rates

Repayment Income	Rate
Below $54,435	Nil
$54,435 – $62,850	1.0%
$62,851 – $66,620	2.0%
$66,621 – $70,618	2.5%
$70,619 – $74,855	3.0%
$74,856 – $79,346	3.5%
$79,347 – $84,107	4.0%
$84,108 – $89,154	4.5%
$89,155 – $94,503	5.0%
$94,504 – $100,174	5.5%
$100,175 – $106,185	6.0%
$106,186 – $112,556	6.5%
$112,557 – $119,309	7.0%
$119,310 – $126,467	7.5%
$126,468 – $134,056	8.0%
$134,057 – $142,100	8.5%
$142,101 – $150,626	9.0%
$150,627 – $159,663	9.5%
$159,664+	10.0%

HECS Repayment = Repayment Income × Applicable Rate

Applied to your total repayment income, not just the amount over the threshold.

Step 6: Calculate Superannuation

Employers must contribute 12% of your Ordinary Time Earnings (OTE) to your super fund. This is on top of your gross pay, not deducted from it.

Super Contribution = Ordinary Time Earnings × 0.12

Superannuation Guarantee rate for 2025-26 is 12%.

Key Points

OTE includes: Base salary, shift loadings, some allowances
OTE excludes: Overtime, most expense reimbursements
Maximum contribution base: $62,500 per quarter ($250,000/year) — super is only mandatory up to this limit

Division 293 Tax (High Earners)

If your income + super contributions exceed $250,000, you pay an additional 15% tax on super contributions. This is called Division 293 tax.

Division 293 = min(Income + Super − $250,000, Super Contributions) × 0.15

Extra 15% tax on super for high earners. Calculated on the lesser of the excess over $250k or total super contributions.

Division 293 affects your super, not your take-home pay. The additional tax is typically paid from your super fund, reducing your retirement savings rather than your current income.

Worked Examples with Real Numbers

Penalty Rate Calculations

Penalty rates multiply your base hourly rate. They stack in a specific order: base → shift → day type → overtime.

Default Penalty Rates

Penalty Type	Typical Range	Notes
Night Shift	15–30%	Applied per shift, varies by award
Saturday	50–100%	Weekend penalty
Sunday	75–200%	Usually higher than Saturday
Public Holiday	150–250%	State-specific holidays apply

Stacking Order

Daily Pay = Base Rate × Hours × Shift Multiplier × Day Multiplier + Allowances

Multipliers are applied sequentially. A night shift on Sunday would be: Base × Night × Sunday.

Award-specific rules vary. Some awards don't allow stacking (the higher penalty applies instead). PayByRoster uses Fair Work standard stacking by default — you can adjust multipliers to match your specific award.

Edge Cases & Special Scenarios

ATO References & Compliance

PayByRoster uses official Australian Taxation Office rates and thresholds. All figures are updated for the 2025-26 financial year.

Official Sources

Disclaimer: PayByRoster provides estimates for informational purposes only. Results should not be considered financial or tax advice. Individual circumstances vary — consult a registered tax professional or accountant for personalised advice.

Need Help?

Found an issue with our calculations or have questions about the methodology?