Itemized vs Standard Deduction Calculator 2026

Income, inputs and rounding. MAGI is the single driver for every threshold and is used as an AGI proxy. Tax-exempt income addbacks and other MAGI adjustments are not modeled. All six money inputs accept commas, turn empty or negative entries into $0, cap at $10,000,000 and round half up to whole dollars ($0.50 rounds up). Invalid numeric text stays visible with an error; the last valid value is retained for the comparison. Year-end ages use the same validation, are limited to 0–120 and keep two decimals. Outputs retain cents. Reset restores the example values, including both spouse ages.

Standard deduction and ordinary brackets — IRC §§1, 63; Rev. Proc. 2025-32 §§4.01, 4.14. §4.14 states: “For taxable years beginning in 2026, the standard deduction amounts under § 63(c)(2) are as follows”; the table gives $32,200 MFJ, $24,150 head of household and $16,100 Single/MFS. Paragraph (3) states: “For taxable years beginning in 2026, the additional standard deduction amount under § 63(f) for the aged or the blind is $1,650. The additional standard deduction amount is increased to $2,050 if the individual is also unmarried and not a surviving spouse.” This tool models age 65+, not blindness: $2,050 Single/HoH, $1,650 for each eligible MFJ spouse, and $1,650 MFS. This age addition applies to the STANDARD path only. Assumes standard-deduction eligibility, including that an MFS spouse does not force itemization. Both federal tax columns use the published 2026 brackets in §4.01.

Senior Deduction (Schedule 1-A) — Pub. L. 119-21 §70103; IRC §151(d)(5)(C). IRS Schedule 1-A guidance makes this deduction available whether you itemize or take the standard deduction. The modeled amount is $6,000 per person age 65+, reduced per eligible person by 6% of MAGI above $75,000 ($150,000 MFJ), never below zero. MFS is ineligible: the enacted statute applies to married individuals “only if the taxpayer and the taxpayer's spouse file a joint return for the taxable year.” The row appears equally on BOTH paths and is subtracted from BOTH taxable incomes. It is outside the Standard − Itemized deduction difference. Assumes required SSNs and other eligibility conditions.

SALT — Pub. L. 119-21 §70120; IRC §164(b)(6). Allowed SALT = min(paid, max(floor, 2026 cap − 30% × max(0, MAGI − threshold))). The cap is $40,400 ($20,200 MFS); phase-down starts above $505,000 ($252,500 MFS); the floor is $10,000 ($5,000 MFS). The crossover MAGI is approximately $606,333.33 ($303,166.67 MFS). With whole-dollar inputs, the first floor input is $606,334 ($303,167 MFS); MAGI $605,000 still gives a $10,400 cap. In 2030 the cap reverts to $10,000/$5,000. §70120 is “Limitation on individual deductions for certain state and local taxes, etc.” The calculator uses income taxes OR sales taxes, plus property taxes, as entered; it does not model a pass-through entity workaround.

Mortgage and medical — IRC §§163(h), 213(a). Qualified acquisition-debt interest is accepted as entered. You must apply the $750,000 debt limit ($375,000 MFS) yourself; older-debt exceptions and debt allocation are not calculated. Medical allowed = max(0, eligible out-of-pocket medical expenses − 7.5% × MAGI). See IRS Publication 936 and Publication 502.

Charity floor, caps and top-bracket simplification — IRC §§170, 68; Pub. L. 119-21 §§70425, 70111. §70425 limits the otherwise allowable deduction to the amount that “exceeds 0.5 percent of the taxpayer's contribution base”. The model combines min(cash, 60% × MAGI) + min(stock, 30% × MAGI), subtracts 0.5% × MAGI once, and floors at zero. It assumes eligible gifts, long-term appreciated stock transferred in kind, and no other donations or carryovers. The Standard path shows $0.00 charity; the separate non-itemizer cash deduction is not modeled.

Pre-charitable taxable income = max(0, MAGI − max(SALT + mortgage + medical, standard path + senior deduction)). If this exceeds the 37% threshold ($640,600 Single/HoH, $768,700 MFJ, $384,350 MFS), the entire modeled charitable amount is multiplied by 35/37 and rounded to cents. This is a simplified blanket factor, not a full IRC §68 calculation. Actual §68 uses “2/37 of the lesser of” otherwise allowable itemized deductions or the statutory income amount above the threshold; it can affect deductions besides charity. Percentage-cap ordering interactions, floor carryovers and gains avoided are not calculated. Miscellaneous itemized deductions subject to IRC §67 are permanently disallowed under OBBBA; no such input is offered.

Comparison and limits. Standard path = base standard deduction + age addition. Itemized path = allowed SALT + mortgage + charity + medical. Each taxable income = max(0, MAGI − that path's deduction − the same senior deduction). Tax difference = standard federal tax − itemized federal tax, including negative values. “Standard is larger by” and “Itemized is larger by” describe deductions, not advice; ties display Standard with “equal — either path”. The model excludes car-loan interest deduction, blindness addition, casualty losses, gambling losses, PTE SALT workarounds, AMT, NIIT at 3.8%, state taxes, Social Security benefit-tax interactions, capital-gains tax and all tax credits. It does not determine your filing eligibility or refund. Illustration only; consult a tax professional.

Sources and access date. IRS/statutory source text checked October 31, 2026: Rev. Proc. 2025-32 §§4.01, 4.14; Pub. L. 119-21 §§70103, 70111, 70120, 70425; IRS Schedule 1-A guidance; IRC §§63, 67, 68, 151, 163(h), 164, 170, 213; Publications 502/936. No unpublished parameters.