How Income Tax Is Calculated — Brackets, Marginal Rates & Worked Examples
How tax brackets actually work
A progressive system divides your taxable income into layers. Each layer is taxed at its own rate; the rates never apply to your whole income. A common myth is that a raise "pushes all your income into a higher bracket" — it doesn't. Only the slice of income above the threshold is taxed at the higher rate.
The general formula
Effective rate = Tax ÷ Taxable income. Marginal rate = the rate of your highest occupied bracket.
Step-by-step example (illustrative brackets)
Assume brackets of 0% up to 10,000 · 10% from 10,001–40,000 · 20% from 40,001–100,000 · 30% above 100,000, with taxable income of 72,000:
First 10,000 → 0% → 0
Next 30,000 (10,001–40,000) → 10% → 3,000
Next 32,000 (40,001–72,000) → 20% → 6,400
Total tax = 9,400 · Effective rate = 9,400 ÷ 72,000 ≈ 13.1% · Marginal rate = 20%
Even though the top bracket is 30%, none of this income reaches it.
Country examples with official calculators
- Pakistan: annual taxable slabs with progressive rates; salaried and non-salaried schedules differ. Try the Pakistan Income Tax Calculator.
- India: new vs old regime choice changes slabs and deductions. Try the India Income Tax Calculator.
- US: federal brackets plus state tax and standard vs itemized deductions. Try the US Income Tax Calculator.
- UK, Canada, Australia: country-specific tools with local rules — see the finance and regional categories.
Deductions people commonly miss
- Retirement/pension contributions that reduce taxable income
- Charitable donations eligible for credits or deductions
- Professional expenses allowed as employment deductions
- Family-related credits and rebates
- Withholding vs final liability — a refund is not free money, it's your own overpayment
India new-regime slabs, worked (FY 2025-26 / AY 2026-27)
India's default new-regime slabs for FY 2025-26, per the Income Tax Department's Budget 2025 announcement:
| Annual income | Rate |
|---|---|
| Up to ₹4,00,000 | Nil |
| ₹4,00,001 – ₹8,00,000 | 5% |
| ₹8,00,001 – ₹12,00,000 | 10% |
| ₹12,00,001 – ₹16,00,000 | 15% |
| ₹16,00,001 – ₹20,00,000 | 20% |
| ₹20,00,001 – ₹24,00,000 | 25% |
| Above ₹24,00,000 | 30% |
The Section 87A rebate makes this table friendlier than it looks: resident individuals with taxable income up to ₹12,00,000 pay zero tax, because the rebate (up to ₹60,000) wipes out the entire liability at that level. Salaried taxpayers also get a ₹75,000 standard deduction, which lifts the effective tax-free salary to about ₹12.75 lakh. Worked example — ₹16,00,000 salary:
Less standard deduction ₹75,000 → taxable ≈ ₹15,25,000
Tax: 5% of 4,00,000 (₹20,000) + 10% of 4,00,000 (₹40,000) + 15% of 3,25,000 (₹48,750) = ₹1,08,750 before cess
Effective rate ≈ 7.1% — against a 15% marginal rate. The marginal-versus-effective gap is the bracket myth, paid off in rupees.
New vs old regime is a genuine computation, not a preference: the old regime has lower exemption (₹2.5 lakh) and rates starting at 5% earlier, but allows deductions the new regime removes (80C investments, HRA, most others). Salaried filers run both with their actual deduction stack and keep the cheaper one — the India income tax calculator does this comparison. Rates above are as announced in Budget 2025; verify against the CBDT's current tables before filing.
Important: Tax rules change yearly and vary by personal situation. This guide explains mechanics, not advice for your specific case — confirm figures against your tax authority's official tables (IRS, HMRC, CBDT, FBR) before filing.
FAQ
Why is my effective rate lower than my bracket rate?
Because lower brackets are filled first at their lower rates, the blended average across all brackets is always below your top marginal rate.
Are bonuses taxed at a higher rate?
No — withholding on bonuses may be higher in some countries, but the final tax is calculated on total annual income. The extra withheld usually comes back as a refund.
What is taxable income?
Gross income minus allowed deductions and exemptions. It is the base the brackets apply to, and it is usually smaller than your gross salary.
Is it worth contributing to retirement accounts for tax savings?
For many earners yes, because contributions reduce taxable income today; the trade-off is locking funds until retirement. Rules and limits vary by country and plan type.