Tax deduction vs tax offset
A deduction lowers income taxed; an offset lowers tax owed.
A deduction reduces your taxable income, so it saves you tax at your marginal rate. A tax offset reduces the tax you owe, dollar for dollar, after the tax is calculated. That makes a $1,000 offset worth more than a $1,000 deduction to almost everyone.
Worked example
On a 32.5% marginal rate, a $1,000 deduction cuts your tax by about $325. A $1,000 offset cuts your tax by the full $1,000 — roughly three times the benefit.
Common mistake
Using the words interchangeably when planning. Chasing extra spending for a deduction only ever returns a fraction of the dollar you spent; an offset you already qualify for costs you nothing.
Grounded in ATO guidance. Figures last checked . General information, not tax advice.
Related terms
Taxable income
Assessable income minus deductions — what tax is actually on.
Marginal tax rate
The tax rate on your next dollar of income.
Substantiation (proving a deduction)
The records that turn a claim into a defensible deduction.
Sole trader tax rate
There isn’t one — you’re taxed at personal marginal rates.
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