Marginal Tax Rate

Australia's income tax scales are progressive: each bracket applies only to the dollars inside it. For 2026-27, the rates are 15 percent from $18,201 to $45,000, 30 percent to $145,000, 37 percent to $190,000 and 45 percent above. The 2 percent Medicare levy sits on top of all of them. The marginal tax rate is the rate on the next dollar earned. A salary of $120,000 sits in the 30 percent bracket, so its marginal rate is 32 percent once the levy is counted.

The average rate is the total tax divided by the total income, and it is always lower than the marginal rate. The same $120,000 salary carries roughly a 24 percent average rate including Medicare. The distinction matters because every financial decision runs on the marginal number. The value of a deduction, the saving from salary sacrifice and the cost of crossing a bracket all price the next dollar. That is why the ATO's tax tables and every pay calculator separate the two.

The brackets are marginal, which is the part the dinner-party mythology gets wrong. On a $120,000 salary, the first $18,200 is tax-free, the next $26,800 is taxed at 15 percent, and the remaining $75,000 at 30 percent: a total of $26,520, plus $2,400 of Medicare levy. The average rate is $28,920 divided by $120,000 - roughly 24 percent - while the marginal rate on the next dollar earned is 32 percent, because that dollar lands inside the 30 percent bracket and attracts the levy.

The raise arithmetic shows the brackets doing their marginal work. A salary moving from $135,000 to $150,000 adds $15,000: the first $10,000 of the raise is taxed at 32 percent and the final $5,000 at 39 percent, because it crosses into the 37 percent bracket. The whole salary does not re-bracket - $135,000 of it keeps its existing treatment. The take-home increase is $9,850, which the marginal tax rate calculator prices on any bracket boundary.

The marginal rate is the multiplier on every deduction and every sacrifice. A $1,000 deduction at a 32 percent marginal rate returns $320; a sacrificed dollar at the same rate saves 32 cents of tax and Medicare on its way to the 15 percent super envelope. The australian income tax calculator runs the full picture, and the tax deduction entry covers why a deduction is a discount, not a refund.

For an Australian reader, the marginal rate is the number that prices every decision the ATO has an opinion on. Deductions, salary sacrifice, franking credits, capital gains and the Medicare Levy Surcharge thresholds all run through it. The average rate tells you what you paid; the marginal rate tells you what the next dollar costs. Confusing the two is how people misprice their own decisions in both directions. The mispricing undervalues small deductions and undervalues pre-tax strategies at the same time.

A colleague named Brent (yes, that Brent) turned down a $15,000 raise because it would "push me into a higher bracket on everything". The brackets are marginal: $135,000 of his salary kept its existing treatment, and the raise was taxed at 32 and 39 percent only on the dollars inside the higher bracket. The raise was worth $9,850 of take-home pay, which is the price of declining it. The highest-leverage thing most Australians can do is learn the marginal rate on their own income. The marginal tax rate calculator prices it in ten seconds, and every deduction and sacrifice decision runs through that number.