Tax Projection Tool

How to read this. Add as many income lines as you want. Each type lands where it should: wages carry payroll tax, 1099 income carries SE tax plus the QBI deduction, interest and short-term gains are taxed as ordinary income but still count toward the NIIT, and long-term gains and qualified dividends get the preferential 0/15/20% rates stacked on top of ordinary income. The standard deduction is automatic. Switch to Itemize to enter SALT, mortgage interest, charitable, and medical, and it warns you the moment you cross a 2026 cap.

Filing-status default. The toggle opens on Married Filing Jointly because the loaded example is a joint household, and switching it to Single or Head of Household re-runs every figure. It's a starting example, not an assumption about you - set it to your own status before reading the numbers.

Child Tax Credit. The 2026 credit is $2,200 per qualifying child, phased out $50 per $1,000 of MAGI over $400,000 (joint) or $200,000 (other). It's modeled the way the law splits it: nonrefundable against your income tax first, then a refundable Additional Child Tax Credit capped at $1,700 per child and limited to 15% of earned income over $2,500. So a lower-income household doesn't always get the full credit back - the tool shows the usable amount, not just the headline. Two edge cases are left out: the alternative ACTC formula for families with three or more qualifying children, and the Earned Income Tax Credit, neither of which this tool computes - a low-income return could qualify for more than shown.

Not modeled (OBBBA deductions). The 2025 law created several new deductions this tool does not calculate: the senior deduction (up to $6,000 for filers 65+), the deductions for qualified tips and overtime, the passenger-vehicle loan interest deduction, and the new above-the-line charitable deduction for non-itemizers ($1,000 single / $2,000 joint). If any apply to you, your real tax is lower than shown. They're left out deliberately rather than half-built; each needs its own inputs and eligibility tests.

Social Security caps are per earner. For Married Filing Jointly, tag each wage and self-employment line E1 or E2. Each earner gets their own $184,500 Social Security wage base, and each earner's self-employment income shares only that earner's remaining room - the way the law works. One person holding several jobs should keep all their lines on the same earner tag (the real system refunds Social Security over-withheld across one person's employers at filing; capping per person mirrors the end result). Medicare and the 0.9% Additional Medicare surtax stay combined per return, as the law requires. Capital-loss entries are limited the way the law limits them: net preferential losses offset at most $3,000 of ordinary income, and this tool does not track carryforwards. Net self-employment losses owe no SE tax but still reduce income.

QBI is an estimate. The 20% qualified-business-income deduction is taken on your 1099 income reduced by the deductible half of self-employment tax, then run through the SSTB and wage/UBIA phase-ins. A fully precise figure would also subtract self-employed health insurance and self-employed retirement contributions from the QBI base, which this tool doesn't collect, so QBI here can be slightly overstated for those filers.

What's modeled for 2026. SALT caps at $40,400 and phases down 30 cents per dollar of MAGI over $505,000, bottoming out at $10,000. Charitable cash gifts lose the first 0.5% of AGI and top out at 60% of AGI. Medical counts only above 7.5% of AGI. If you land in the 37% bracket, OBBBA's new value limit trims your itemized deductions by 2/37 of the amount sitting in that bracket, so a dollar of deduction is worth about 35 cents instead of 37. That haircut is applied here, not just flagged. Mortgage interest assumes your loan stays inside the $750,000 principal limit. Still left out: AMT and state-specific itemized rules.

ACA is a cliff estimator, not a subsidy calculator. The enhanced premium tax credits expired December 31, 2025, so the 400%-of-poverty subsidy cliff is back as of January 1, 2026. Eligibility for 2026 coverage runs off the 2025 HHS poverty guidelines, and a household one dollar over 400% FPL gets nothing. The panel shows where you sit against the cliff and your headroom, not your actual premium tax credit - that needs the benchmark Silver premium, ages, and rating area the tool doesn't collect. MAGI here is approximated as AGI and does not add back muni-bond interest, untaxed Social Security, or excluded foreign income; see the note in the panel.

State tax is simplified. Most states run off one flat base - gross income less deferrals, the ½SE deduction, the QBI deduction and the state standard deduction - through their 2026 brackets. A few are modeled with their own mechanics where the simple base would be materially wrong: South Carolina's SCIAD phase-out and Utah's taxpayer tax credit (a flat 4.5% with a credit, not a deduction; its personal-exemption count is approximated from your qualifying children and should be confirmed against the TC-40). Real states still vary in ways this doesn't fully capture: some start from federal AGI and others from taxable income, most don't follow the federal QBI deduction, local income taxes aren't included, and several tax capital gains, retirement income, or credits differently. Treat the state number as a close estimate, not a return.

This is an estimate, not financial or tax advice, and not a filing tool. Figures are projections based on published rates and your inputs. Consult a qualified professional before making decisions.

Sources. Federal brackets, the standard deduction, and the Social Security wage base are from the IRS 2026 inflation update (Revenue Procedure 2025-32). The SALT cap, the charitable floor, and the 37%-bracket limit on itemized deductions come from the 2025 tax law (the One Big Beautiful Bill Act). State brackets and standard deductions are the Tax Foundation's 2026 tables, updated for legislation enacted through mid-June 2026 (Georgia HB 463, Arkansas's 2026 special session with its dual-table structure, Utah SB 60 with TC-40 credit mechanics, and South Carolina H.4216, each retroactive to January 1, 2026). California SDI reflects the EDD's 2026 rate. The poverty figures behind the ACA cliff are the 2025 HHS guidelines, which is the set 2026 coverage runs on.

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