Calculating Income Tax

Apply Australian income tax brackets and the Medicare levy to calculate tax payable, then determine refunds or debts from PAYG withheld.

55 min MS-F1 4 MC 4 WE Lesson 8 of 14 Free
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Think First

Australia uses a progressive tax system — the more you earn, the higher the rate you pay on each extra dollar. But here's the key word: progressive means only the income in each bracket gets taxed at that bracket's rate, not your entire income. If you earn $90,000, you are NOT paying 32.5% on all of it. Think about what that actually means in dollars before we apply any numbers — and think about why a government might design a tax system this way rather than just charging everyone the same flat percentage.

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Key Relationships — This Lesson

$\text{Income tax} = \text{Base amount} + \text{Marginal rate} \times (\text{Taxable income} - \text{Threshold})$
Base amount and threshold come from the tax table  |  marginal rate applies only above the threshold
$\text{Medicare levy} = \text{Taxable income} \times 0.02$
2% of taxable income  |  calculated separately and added to income tax
$\text{Total tax liability} = \text{Income tax} + \text{Medicare levy}$
This is what the worker actually owes the ATO for the year
Refund = PAYG withheld − Total tax liability  (when PAYG > liability)  |  Debt = Total tax liability − PAYG withheld  (when liability > PAYG)

Know

  • The 2024–25 Australian income tax brackets and how to read them
  • That Medicare levy = 2% of taxable income, added separately
  • The formulas for tax refund and tax debt

Understand

  • Why the marginal rate applies only to income above the bracket threshold
  • Why effective tax rate is always lower than the marginal rate
  • How PAYG withholding is reconciled against actual tax liability at year end

Can Do

  • Calculate income tax from a tax table for any taxable income
  • Add Medicare levy to find total tax liability
  • Determine whether a worker receives a refund or owes a debt, and by how much

Misconceptions to Fix

Wrong: Income tax is calculated using a single flat rate for all income.

Right: Australia uses a progressive tax system with marginal tax rates. Different portions of income are taxed at different rates, not the entire amount at one rate.

Key Terms
Progressive TaxA tax system where higher income earners pay a higher percentage of their income in tax.
Marginal Tax RateThe rate of tax applied to the last dollar earned within a particular tax bracket.
Tax BracketA range of income that is taxed at a particular rate.
Tax PayableThe total amount of income tax owed to the government before offsets.
Tax OffsetA direct reduction in the amount of tax payable, such as the low income tax offset.

How Progressive Tax Brackets Work

In a progressive tax system, each portion of income is taxed at a different rate — higher rates apply only to the income within that bracket, not to total income.

The 2024–25 Australian income tax brackets for residents are shown below. The base amount is the total tax already accumulated at the bottom of the bracket. You add to it the marginal rate applied only to income above the bracket's lower threshold.

Tax on this income
Column B
HOW BRACKETS WORK — EXAMPLE: $70,000 TAXABLE INCOME $0 – $18,200 0% → $0 tax $18,201 – $45,000 19% → $5,092 tax $45,001 – $70,000 32.5% → $8,125 tax Total income tax = $0 + $5,092 + $8,125 = $13,217 Effective rate = $13,217 ÷ $70,000 = 18.9% — not 32.5% The 32.5% marginal rate applies only to the $25,000 above $45,000 — not to the full $70,000
Each bracket is taxed at its own rate. The marginal rate is NOT applied to the whole income.
Always use the taxable income figure, not gross income: The tax table is applied to taxable income (after deductions). Using gross income gives a higher — and incorrect — tax figure.
Common error — The marginal rate applies only to income above the threshold: A taxable income of $70,000 is in the $45,001–$120,000 bracket. Tax = $5,092 + 0.325 × ($70,000 − $45,000) = $5,092 + $8,125 = $13,217. The 32.5% rate applies only to the $25,000 above $45,000 — NOT to the full $70,000.

Medicare Levy

The Medicare levy is an additional 2% charge on taxable income that funds Australia's universal health system — it is added on top of income tax to find total tax liability.

Most Australian taxpayers pay a Medicare levy of 2% of their taxable income. The total tax liability is:

$$\text{Total tax liability} = \text{Income tax (from brackets)} + \text{Medicare levy}$$
Example taxable incomeIncome taxMedicare levy (2%)Total liabilityEffective rate
$50,000$6,717$1,000$7,71715.4%
$70,000$13,217$1,400$14,61720.9%
$100,000$22,967$2,000$24,96725.0%
Add Medicare levy after calculating income tax — as a separate step: Calculate bracket tax first, then add 2% of taxable income. Do not include it in the bracket calculation.
Common error — Medicare levy is 2% of taxable income, not of tax payable: A common error is applying 2% to the income tax figure rather than to the taxable income. For a $70,000 income: correct Medicare = $70,000 × 0.02 = $1,400; incorrect = $13,217 × 0.02 = $264 — a very different result.
Insight — Effective vs marginal rate: For a $70,000 income, the marginal rate is 32.5% but the effective rate (total tax ÷ taxable income) is only 20.9%. This is the difference between the rate on your last dollar earned and the average rate across all your income — they are never the same in a progressive system.

Tax Refund or Tax Debt — Reconciling PAYG

At the end of each financial year, Australians lodge a tax return comparing what was withheld by their employer against what they actually owe — the difference is either a refund or a debt.

Throughout the year, employers withhold PAYG tax from each pay packet and send it to the ATO. This is an estimate — it may be more or less than the actual tax liability. The reconciliation process:

Action
Column B
PAYG WITHHELD vs TOTAL TAX LIABILITY PAYG vs Liability? PAYG > Liability REFUND ATO pays you Liability > PAYG DEBT You pay ATO Always state the outcome as "refund of $X" or "debt of $X" — not just a number
The direction of the comparison determines whether it's a refund or a debt.
State whether the outcome is a refund or a debt — and by how much: Don't just write a number. Write "Tax refund of $X" or "Tax debt of $X." The conclusion earns a mark in extended response questions.
Common error — Compare PAYG to (income tax + Medicare levy), not income tax alone: The comparison is always: PAYG withheld vs total tax liability (income tax + Medicare levy combined). Forgetting to include the Medicare levy before comparing understates the liability.

A Reliable Strategy for Tax Table Questions

Tax questions feel intimidating because the table looks formal, but the process is actually very repetitive once you know the order.

  1. Find the correct bracket for the taxable income
  2. Write the base tax amount from the table
  3. Subtract the lower threshold from the taxable income
  4. Apply the marginal rate only to that excess amount
  5. Add the base amount and marginal component
  6. Then calculate Medicare levy separately
Exam technique: Write the bracket first, for example "$84,000 is in the $45,001–$120,000 bracket." That one line often prevents students from using the wrong base amount or threshold.
Reasonableness check: If your tax payable is more than the taxable income, or if the Medicare levy is only a few dollars on a high income, something has gone wrong in the setup.

Worked Examples

Worked Example 1 Full Tax Calculation — Refund

Problem

Zara has a taxable income of $67,500 for the 2024–25 financial year. Her employer withheld $14,980 in PAYG tax. Calculate: (a) income tax payable, (b) Medicare levy, (c) total tax liability, and (d) whether she receives a refund or owes a debt, and by how much.

Solution

1 $\$67{,}500 \text{ falls in the } \$45{,}001\text{–}\$120{,}000 \text{ bracket}$ Identify the correct bracket from the tax table
Worked Example 2 Tax Debt Outcome

Problem

Marcus has a taxable income of $112,000. His PAYG withheld for the year was $28,100. Calculate his total tax liability and determine whether he has a refund or debt.

Solution

1 $\$112{,}000 \text{ falls in the } \$45{,}001\text{–}\$120{,}000 \text{ bracket}$ Identify the correct bracket
Worked Example 3 Full Question — Income to Refund/Debt

Problem

Priya earns $82,600 salary and $1,200 in bank interest. Her allowable deductions total $2,850. Her PAYG withheld was $19,400. Calculate her tax refund or debt.

Solution

1 $\text{Gross income} = \$82{,}600 + \$1{,}200 = \$83{,}800$ Sum all assessable income
Worked Example 4 Bracket Boundary Check

Problem

Ella has a taxable income of $45,000 exactly. Her PAYG withheld for the year was $5,900. Calculate her income tax, Medicare levy, total tax liability, and whether she receives a refund or owes a debt.

Solution

1 $\$45{,}000 \text{ is at the top of the } \$18{,}201\text{–}\$45{,}000 \text{ bracket}$ Use the 19c per dollar over $18,200 rule
Revisit Your Initial Thinking

Look back at what you wrote in the Think First section. What has changed? What did you get right? What surprised you?

Check Your Understanding

Checkpoint Questions

Select the best answer for each question. Feedback appears after you choose.

MC

Multiple Choice

5 random questions from a replayable lesson bank — feedback shown immediately

B) $16,900.00
C) $6,422.00
D) $5,092.00

A taxpayer's income tax is $18,450 and their taxable income is $84,000. What is their total tax liability including Medicare levy?

A) $18,819.00
B) $20,130.00
C) $19,137.00
D) $17,061.00

A taxpayer's total tax liability is $22,640. Their PAYG withheld was $21,980. Which statement is correct?

A) They receive a refund of $660
B) They owe a tax debt of $660
C) They receive a refund of $22,640
D) No refund or debt — they break even

A taxpayer has taxable income of $45,000. What is their Medicare levy?

A) $90
B) $509.20
C) $900
D) $1,800

Written Response Practice

These questions focus on setting up the bracket calculation cleanly and finishing with the correct refund/debt conclusion.

Short Answer 1

A taxpayer has taxable income of $60,000. Calculate their income tax payable before Medicare levy.

Short Answer 2

A taxpayer has taxable income of $72,000. Their PAYG withheld for the year was $15,600. Calculate their total tax liability including Medicare levy, and determine whether they receive a refund or owe a debt.

Short Answer 3

A taxpayer's taxable income is $95,000 and PAYG withheld was $22,000. Calculate whether they receive a refund or owe a debt.

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Tax Bracket Quickfire

Use this as a fast setup drill: bracket first, Medicare second, refund/debt conclusion last.

Which part of income is taxed at the marginal rate?

A) The full taxable income
B) Only the part above the bracket threshold
C) Only the PAYG withheld
D) Only the Medicare levy

What is the Medicare levy on a taxable income of $80,000?

A) $160
B) $800
C) $1,200
D) $1,600

If PAYG withheld is greater than total tax liability, what is the result?

A) A refund
B) A debt
C) A deduction
D) A salary sacrifice

Why should Medicare levy be added before deciding whether there is a refund or debt?

A) Because it changes the tax bracket
B) Because it replaces PAYG withheld
C) Because it is part of the total tax liability
D) Because it is deducted from gross income
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