About this tool
The Alternative Minimum Tax was designed to ensure high earners pay something despite deductions. AMTI strips most itemized deductions, adds ISO exercise spread, and applies flat 26/28 percent rates. You pay the higher of regular tax or AMT. ISO exercises are the most common AMT trigger.
How it works
AMTI = AGI - exemption (phased out) + ISO spread; tentative_AMT = 26% × AMTI up to threshold + 28% above
Enter AGI, itemized deductions, any ISO exercise spread, and filing status. The calculator estimates AMTI, applies exemption, computes tentative AMT, and compares to regular tax.
How income tax brackets work
Almost every modern country uses a progressive tax system: you pay a low rate on the first slice of income, a higher rate on the next slice, and so on. Critically, moving into a higher bracket does NOT raise the tax on income below the bracket boundary - only the income above it.
Example with simplified brackets: 10% up to $10K, 20% from $10K to $50K, 30% above $50K. On $60K income:
- First $10K: $1,000 tax (10%)
- Next $40K: $8,000 tax (20%)
- Last $10K: $3,000 tax (30%)
- Total: $12,000 tax = 20% effective rate, not 30%.
Marginal vs effective rate
Two numbers you'll see on every tax calculator:
| Rate type | Definition | Use it for |
|---|
| Marginal | Rate on your NEXT dollar of income | Deciding whether to take overtime, a bonus, or a second job. Estimating value of a deduction. |
| Effective / Average | Total tax / total income | Comparing tax burden across countries or states. Budgeting. |
Effective rate is always lower than marginal rate (unless you're in the lowest bracket). The gap widens as income rises.
2026 federal income tax brackets compared
| Country | Lowest rate | Top rate | Bracket count | Top rate starts at |
|---|
| US (federal) | 10% | 37% | 7 | $626,350 single / $751,600 MFJ |
| UK (Eng/Wales/NI) | 20% | 45% | 3 + PA | £125,140 |
| UK (Scotland) | 19% | 48% | 6 + PA | £125,140 |
| Canada (federal) | 15% | 33% | 5 | CAD 246,752 |
| Australia | 16% | 45% | 5 | AUD 190,000 |
| India (new regime) | 0% | 30% | 7 | Rs 24 lakh |
| India (old regime) | 0% | 30% | 4 | Rs 10 lakh |
| Germany | 0% | 45% | Continuous formula + Reichensteuer | EUR 277,825 |
| Singapore | 0% | 24% | 12 | SGD 1,000,000 |
| UAE | 0% | 0% | n/a | n/a (no personal income tax) |
Most-missed tax-saving levers
- Retirement contributions - 401(k), RRSP, EPF, NPS, super all reduce taxable income today. Employer matching is typically a 50-100% instant return.
- Health spending - HSA (US), salary sacrifice (UK), group health (India 80D) - pre-tax medical spend.
- Home loan interest - deductible in US (with SALT cap), UK BTL, India 80EEA, Canada (rental only), Germany.
- Education - 529 (US), Junior ISA (UK), 80C (India), RESP (Canada).
- Charitable giving - 60% AGI cap (US), gift aid (UK), 80G (India), donation tax credit (Canada).
- Capital losses - offset capital gains in same year + carry forward.
- Tax-loss harvesting - realize paper losses to offset realized gains. Watch the wash-sale rule (30 days US, 30 days UK).
Frequently asked questions
Why does AMT exist?
1969 law to stop wealthy taxpayers from zeroing out via deductions. Now mostly hits high-income with ISOs or large state taxes (capped at $10K SALT).
Common AMT triggers?
ISO exercises (huge), high state income tax, large family with many dependents.
Get back the AMT later?
Yes - AMT credit (Form 8801) for AMT paid that wasn't due to truly preferential items. Recoverable in future regular-tax years.
Avoid AMT?
Don't exercise ISOs across high-income years. Time itemized deductions. Convert to Roth in low-income years.
Will moving to a higher bracket cost me money?
Almost never. Only the income above the bracket boundary is taxed at the higher rate. Income below it stays at the lower rate. The exceptions are 'cliff' benefits - some welfare programs end at hard income thresholds rather than phase out smoothly.
Is it better to invest in retirement or pay down debt?
Compare expected after-tax investment return to interest rate on the debt. Tax-advantaged retirement with employer match almost always wins. High-interest credit-card debt (>15%) wins over almost any investment.
How accurate is this calculator for my situation?
It applies the official brackets, standard deduction, and FICA/NI/CPP/EI rates for the year you select. It does NOT model itemized deductions, dependents, education credits, or self-employment - which can shift your final liability ±5-15%. Use the result as a starting estimate.
What's the difference between tax credits and deductions?
Deductions reduce your taxable income before tax is calculated. Credits reduce your tax bill dollar-for-dollar. A $1,000 deduction at the 22% bracket saves $220 in tax. A $1,000 credit saves $1,000. Credits are more valuable per dollar.
When should I update my withholding?
After major life events: marriage, divorce, baby, new job, large bonus, home purchase. Otherwise once a year, after filing, to align with the previous year's actual liability. The IRS Tax Withholding Estimator and HMRC PAYE adjustments handle this.
How accurate is the AMT Calculator?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the AMT Calculator free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Can I use the AMT Calculator on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum.
Does the AMT Calculator work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
How do I report a bug or suggest improvement to the AMT Calculator?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours.
Can I share results from the AMT Calculator?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another amt tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.
