How It Works
Subtract deductions from taxable income to find the income that is taxed.
Progressive tax = sum over each band of (income in band x band rate)
- For each band, take only the income that falls inside it and multiply by that band rate.
- Add the tax from every band, then subtract any tax credits to get the total tax.
- Divide total tax by income for the effective rate; the marginal rate is the rate of the top band your income reaches.
Worked Example
Income is 60,000 with no deductions, using bands of 0% up to 10,000, 10% up to 40,000, 20% up to 85,000, and a 30% top rate.
Band 1 (0 to 10,000) at 0%
10,000 x 0% = 0
Band 2 (10,000 to 40,000) at 10%
30,000 x 10% = 3,000
Band 3 (40,000 to 60,000) at 20%
20,000 x 20% = 4,000
Total tax
0 + 3,000 + 4,000 = 7,000
Effective rate
7,000 / 60,000 = 11.67%
Marginal rate
20% (top band reached)
The total tax is 7,000, leaving 53,000 after tax. The effective rate is 11.67%, well below the 20% marginal rate, because only the slice of income inside the top band is taxed at 20%. A common mistake is multiplying the whole income by the marginal rate, which here would wrongly give 12,000; progressive systems tax each band separately, so the effective rate is always lower than the marginal rate.
Income Tax: How Progressive Bands Work
Why each slice of income pays its own rate
A progressive system never taxes your whole income at one rate. It cuts earnings into layers and charges each layer the rate attached to its band, so a higher bracket only ever touches the income that actually reaches it. Crossing a threshold does not reprice the income beneath it; it only sets the rate on the next layer up. That single design choice is why the headline rate you hear quoted for a salary almost never matches the share of income that genuinely leaves your pocket. This calculator takes your taxable income, deductions, the upper limit and rate of each band, and any credits, then reports the total tax, the effective and marginal rates, and what is left after tax, with every band fully editable so you can drop in the thresholds the IRS publishes for your own filing status and tax year.
Deductions shrink the base; credits cut the bill
Two levers reduce what you owe, and they are not interchangeable. A deduction lowers the income the bands are applied to, so its value is the deduction multiplied by the rate of the band it sits in — a 1,000 deduction is worth 220 in a 22% band but only 100 in a 10% band. A credit is subtracted from the tax itself after the bands have done their work, so it is worth its face value to anyone who can use it, regardless of bracket. Mixing the two up is one of the easiest ways to misread a return: this tool keeps them separate, applying deductions before the bands and credits after, exactly as a real computation does.
Two rates, two different questions
The total tax is the headline, but the two rates are what give it meaning, and they answer genuinely different questions. The marginal rate is the rate on your next unit of income — the figure to reach for when weighing overtime, a bonus, or whether an extra retirement contribution is worth it, because it prices a change at the edge of your income. The effective rate is total tax divided by total income, the blended average that describes what your whole income cost. Under a graduated schedule the effective rate always sits below the marginal rate, because the lowest bands are taxed lightly or not at all, and the gap between the two widens the more of your income is sheltered in those early bands.
Why withholding is rarely the final number
The tax your employer withholds from each paycheck is an estimate built from a form and a pay-period formula, not a settled liability. It does not know about a second job, a working spouse, freelance income, mid-year raises, or the deductions and credits you will actually claim. The real figure is reconciled only when the return is filed, and the difference shows up as a refund or a balance due. A band-based estimate like this one is useful precisely because it works from your full annual picture rather than a single payslip, but it is still a projection — the authoritative number is the one on the assessed return.
Errors that inflate the bill
The most expensive mistake is taxing your entire income at the top rate, which on the worked figures would overstate the tax by thousands and feeds the persistent myth that a raise can leave you worse off. A subtler error is treating deductions and credits as the same lever when, as above, they bite in very different places. The third is leaving placeholder bands in place: thresholds and rates are adjusted most years and differ by filing status and residency, so a stale schedule quietly produces a wrong answer. Always swap the defaults for the current, verified figures for your jurisdiction and tax year before trusting the output.
From payslips to national systems
People reach for a band-based estimate to budget, to weigh a salary offer, or to sanity-check a payslip against what was withheld. The same progressive logic sits underneath most national income tax systems, even where the labels, the number of bands, and the surcharges layered on top differ. Because the figures carry no fixed currency, the method travels to any country the moment you enter its own bands. Treat the result as a planning estimate to confirm against the published IRS brackets or with a qualified tax professional, never as the filed computation itself.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.