{"tool":{"slug":"amt","name":"AMT calculator","version":"2026-08-22","canonicalUrl":"https://carlo.finance/tools/amt","jsonUrl":"https://carlo.finance/tools/amt.json","pageUrl":"https://carlo.finance/tools/amt","parameters":[{"key":"income","label":"Ordinary income","unit":"usd-per-year","min":0,"max":100000000,"default":250000,"sourceId":null,"help":"Wages for the year before the exercise, box 1 of your W-2. This is what your regular tax is computed on, and the regular tax is the number the AMT has to beat before you owe anything extra."},{"key":"iso","label":"ISO bargain element","unit":"usd","min":0,"max":50000000,"default":150000,"sourceId":"irs-form-3921","help":"Shares exercised times the gap between the share price on the exercise date and your strike price. On the Form 3921 your employer sends, that is box 4 minus box 3, times box 5. Invisible to regular tax, fully counted by the AMT."},{"key":"salt","label":"State and local tax paid","unit":"usd-per-year","min":0,"max":10000000,"default":0,"sourceId":"pl-119-21-obbba","help":"State income tax and property tax paid during the year. It lowers your regular tax if itemizing beats the standard deduction, capped at $40,000 for 2025, and the AMT adds every dollar of it back on line 2a."},{"key":"pab","label":"Private activity bond interest","unit":"usd-per-year","min":0,"max":10000000,"default":0,"sourceId":"irs-form-6251","help":"Tax-exempt interest from specified private activity bonds, box 9 of your Form 1099-INT. Exempt from regular tax, taxed by the AMT on line 2g. Ordinary municipal bond interest does not go here."}],"options":[{"key":"status","label":"Filing status","options":[{"value":"single","label":"Single"},{"value":"married-joint","label":"Married filing jointly"},{"value":"married-separate","label":"Married filing separately"},{"value":"head-of-household","label":"Head of household"},{"value":"qualifying-surviving-spouse","label":"Qualifying surviving spouse"}],"default":"single","sourceId":null,"help":"Your status on the last day of the year. It sets the AMT exemption on line 5 and the income at which that exemption starts to disappear."}]},"taxYear":2025,"inputs":{"income":250000,"iso":150000,"salt":0,"pab":0,"status":"single"},"result":{"amt":30527,"amtApplies":true,"isoRoom":38188,"roomLeft":0,"overshoot":111812,"regularTax":52023,"tentativeMinimumTax":82550,"amti":400000,"exemption":88100,"baseExemption":88100,"exemptionLost":0,"phaseOutThreshold":626350,"phaseOutCompleteThreshold":978750,"taxableExcess":311900,"rateThreshold":239100,"totalTax":83000,"totalTaxWithoutIso":52473,"isoCost":30527,"agi":250000,"deduction":15750,"itemized":false,"taxableIncome":234250,"effectiveRate":20.75,"marginalOnSpread":28,"form6251":[{"line":"1","label":"Taxable income from Form 1040","amount":234250},{"line":"2a","label":"Deduction added back","amount":15750},{"line":"2g","label":"Private activity bond interest","amount":0},{"line":"2i","label":"ISO exercise adjustment","amount":150000},{"line":"4","label":"Alternative minimum taxable income","amount":400000,"emphasis":true},{"line":"5","label":"AMT exemption","amount":88100},{"line":"6","label":"Income the AMT rates apply to","amount":311900,"emphasis":true},{"line":"7","label":"Tentative minimum tax","amount":82550},{"line":"10","label":"Your regular tax","amount":52023},{"line":"11","label":"Alternative minimum tax","amount":30527,"emphasis":true}],"computability":{"status":"final","fileReady":true,"blocking":[]}},"drivers":[{"key":"iso","label":"ISO bargain element","step":10000,"amtDelta":2800,"totalDelta":2800,"sentence":"Another $10,000 of bargain element adds $2,800 of AMT, which is 28.0 cents on the dollar."},{"key":"income","label":"Ordinary income","step":25000,"amtDelta":-1261.75,"totalDelta":7225,"sentence":"Another $25,000 of salary cuts the AMT by $1,262, because it raises your regular tax by $8,262 and the AMT is only the amount the tentative minimum tax exceeds it by."},{"key":"salt","label":"State and local tax paid","step":10000,"amtDelta":0,"totalDelta":0,"sentence":"Another $10,000 of state and local tax changes nothing: itemizing that much is still worth less than the $15,750 standard deduction, so you would not itemize."}],"sensitivity":{"bySpread":[{"iso":0,"amt":0,"totalTax":52473,"costPerDollar":0},{"iso":38188,"amt":0,"totalTax":52473,"costPerDollar":0},{"iso":75000,"amt":9571,"totalTax":62044,"costPerDollar":12.76},{"iso":150000,"amt":30527,"totalTax":83000,"costPerDollar":20.35},{"iso":225000,"amt":51527,"totalTax":104000,"costPerDollar":22.9},{"iso":300000,"amt":72527,"totalTax":125000,"costPerDollar":24.18}],"byStatus":[{"status":"single","label":"Single","amt":30527,"isoRoom":38188,"totalTax":83000},{"status":"married-joint","label":"Married filing jointly","amt":30724,"isoRoom":33669,"totalTax":68858},{"status":"married-separate","label":"Married filing separately","amt":38406,"isoRoom":12835,"totalTax":91554},{"status":"head-of-household","label":"Head of household","amt":34786,"isoRoom":21807,"totalTax":83000},{"status":"qualifying-surviving-spouse","label":"Qualifying surviving spouse","amt":30724,"isoRoom":33669,"totalTax":69308}]},"assumptions":[{"key":"income","label":"Ordinary income","value":250000,"unit":"usd-per-year","provided":false,"source":null},{"key":"iso","label":"ISO bargain element","value":150000,"unit":"usd","provided":false,"source":{"id":"irs-form-3921","name":"IRS Form 3921, Exercise of an Incentive Stock Option","url":"https://www.irs.gov/forms-pubs/about-form-3921","asOf":"2025-01-01","note":"The statement your employer files when you exercise. Boxes 3, 4, and 5 are where the bargain element on this page comes from."}},{"key":"salt","label":"State and local tax paid","value":0,"unit":"usd-per-year","provided":false,"source":{"id":"pl-119-21-obbba","name":"One Big Beautiful Bill Act (P.L. 119-21)","url":"https://www.govinfo.gov/app/details/PLAW-119publ21","asOf":"2025-07-04","note":"The statute behind the 2025 standard deduction and the $40,000 cap on the state and local tax deduction, both of which change what the AMT adds back."}},{"key":"pab","label":"Private activity bond interest","value":0,"unit":"usd-per-year","provided":false,"source":{"id":"irs-form-6251","name":"IRS Instructions for Form 6251","url":"https://www.irs.gov/instructions/i6251","asOf":"2025-01-01","note":"The form itself: the line numbers this page walks, which adjustments go on which line, and the order they are applied in."}},{"key":"status","label":"Filing status","value":"single","unit":"choice","provided":false,"source":null}],"sources":[{"id":"rev-proc-2024-40","name":"IRS Rev. Proc. 2024-40 (2025 inflation-adjusted items)","url":"https://www.irs.gov/pub/irs-drop/rp-24-40.pdf","asOf":"2025-01-01","note":"The AMT exemption amounts, the income where the exemption starts phasing out, and the point where the 26% AMT rate becomes 28%, for tax year 2025."},{"id":"usc-title-26","name":"26 U.S.C. (Internal Revenue Code)","url":"https://uscode.house.gov/browse/prelim@title26","asOf":"2025-01-01","note":"The sections this page computes and cites: § 55 the alternative minimum tax, § 56(b)(3) the ISO exercise adjustment, § 53 the minimum tax credit, and § 422 the rules that make an option incentive stock."},{"id":"irs-form-6251","name":"IRS Instructions for Form 6251","url":"https://www.irs.gov/instructions/i6251","asOf":"2025-01-01","note":"The form itself: the line numbers this page walks, which adjustments go on which line, and the order they are applied in."},{"id":"irs-form-3921","name":"IRS Form 3921, Exercise of an Incentive Stock Option","url":"https://www.irs.gov/forms-pubs/about-form-3921","asOf":"2025-01-01","note":"The statement your employer files when you exercise. Boxes 3, 4, and 5 are where the bargain element on this page comes from."},{"id":"pl-119-21-obbba","name":"One Big Beautiful Bill Act (P.L. 119-21)","url":"https://www.govinfo.gov/app/details/PLAW-119publ21","asOf":"2025-07-04","note":"The statute behind the 2025 standard deduction and the $40,000 cap on the state and local tax deduction, both of which change what the AMT adds back."}],"warnings":[{"code":"minimum-tax-credit","message":"AMT paid because of an ISO exercise becomes a minimum tax credit under section 53, which you claim on Form 8801 in later years when your regular tax is above your tentative minimum tax. This calculator does not compute that credit, so the figure above is what the exercise costs you in cash this year, not what it costs you forever."},{"code":"same-year-sale","message":"Selling the shares before December 31 of the year you exercised makes it a disqualifying disposition. The spread stops being an AMT adjustment and becomes ordinary wage income instead, so the AMT here goes away and regular tax goes up. That is a different return from the one on this page, and it is the usual way out of an AMT bill you cannot pay."}],"disclaimer":"This computes the federal alternative minimum tax for tax year 2025 on ordinary income plus an incentive stock option exercise, using a real Form 6251. It leaves out state AMT, which California and a few other states charge separately, the minimum tax credit the AMT creates for later years, and capital gains or qualified dividends, which need a Form 6251 Part III worksheet this page does not run. It is not your return and not tax advice. Check anything that matters against your own filing."}