How Do Income Tax Brackets Work?

Turkey calculates income tax using a progressive bracket system: your entire income isn't taxed at one flat rate — only the slice of income that falls within each bracket is taxed at that bracket's rate.

How the bracket system works

Turkey currently applies five brackets at 15%, 20%, 27%, 35% and 40%. The lira thresholds for each bracket are revalued every year, so rather than quoting a fixed amount here, check the current 2026 thresholds on the Turkish Revenue Administration's (GİB) official site.

The logic in practice

Say the first bracket threshold is X and its rate is 15%: the portion of your income up to X is taxed at 15%, the portion above X up to the next threshold is taxed at the next rate, and so on up the brackets. The total tax paid ends up lower than if the whole income were taxed at the top rate alone.

Why it matters

Misreading how brackets work leads people to bad decisions. The classic one is turning down a raise because it would "push me into a higher bracket and I'd take home less." That can't happen under a progressive system. The higher rate applies only to the part of income above the threshold. Tax on everything below it stays the same, so a raise always leaves you with more money, even though you pay more tax.

Marginal rate vs. average rate

Your marginal rate is the rate on the next lira you earn, meaning the rate of the highest bracket you reach. Your average, or effective, rate is total tax divided by total income. With brackets, the average rate is always at or below the marginal rate. Use the average rate when budgeting, and the marginal rate when deciding whether extra work or a raise is worth it.

A made-up example

To show the logic, here are invented round numbers, not Turkey's real ones: 10% on the first 100,000 TRY, and 20% on income between 100,000 and 300,000 TRY. Someone earning 250,000 TRY pays 10,000 TRY on the first slice and 30,000 TRY on the 150,000 TRY in the second slice. Total tax is 40,000 TRY. The average rate is 16%, while the marginal rate is 20%. Taxing the whole amount at 20% would wrongly give 50,000 TRY. Real rates and thresholds change every year, so check GİB, Turkey's tax authority, before calculating.

Common mistakes

Using last year's thresholds for this year's income.
Assuming salary and other income, such as rent or freelance fees, always follow the same schedule. The rules can differ by income type.
Calculating on gross income without first subtracting exemptions and deductions.
Mistaking the marginal rate for your overall tax burden.

When to ask a tax adviser

If you have several income sources, aren't sure whether you need to file an annual return, or earn money from abroad, talk to an accountant. The bracket logic is simple, but filing obligations and exemptions depend on your circumstances.