2026 Standard vs. Itemized Deduction Calculator

The standard deduction is a filing-status amount that reduces taxable income without listing Schedule A expenses. Itemizing instead uses eligible category amounts after their separate floors, caps, and limitations.

Itemizing usually becomes useful when the complete modeled itemized path produces lower federal income tax, not merely when raw receipts exceed the basic standard deduction. This calculator compares two full regular federal income-tax scenarios.

For 2026, the base amounts are $16,100 for Single and Married Filing Separately, $32,200 for Married Filing Jointly and Qualifying Surviving Spouse, and $24,150 for Head of Household.

The base amount can be replaced by the dependent formula or increased by eligible age and blindness additions. A forced-itemization MFS assumption makes the standard deduction unavailable in this model.

Each eligible age-65-or-older or blindness box adds $2,050 for Single and Head of Household, or $1,650 for married filers and a Qualifying Surviving Spouse. Married Filing Jointly can include the corresponding spouse boxes.

The form asks whether age 65 was reached by the end of 2026 rather than inferring age from a birth year. It does not verify blindness certification or rare MFS spouse-related exceptions.

For a supported dependent, the basic standard deduction is the smaller of the regular filing-status amount or the larger of $1,350 and earned income plus $450. The result can still receive eligible age or blindness additions.

TaxArith supports dependent mode only for Single and Married Filing Separately. It does not decide whether another taxpayer is legally entitled to claim the user.

A taxpayer filing Married Filing Separately generally cannot claim the standard deduction when the spouse itemizes on a separate return. Selecting that assumption sets the standard deduction and non-itemizer charity deduction to zero and marks itemizing as required.

The unavailable standard path is not presented as a legal recommendation. MFS community-property issues and uncommon spouse-related additional-deduction rules remain outside this planning model.

Beginning in 2026, this model allows eligible cash contributions outside itemizing up to $1,000 for most supported statuses or $2,000 for Married Filing Jointly. This deduction is separate from Schedule A and is added after the modeled standard deduction.

Noncash contributions do not increase the non-itemizer amount. Organization eligibility, substantiation, contribution limits, and other requirements must be determined outside TaxArith.

The calculation first subtracts reimbursements and tax-free payments from paid medical and dental expenses. It then applies the statutory AGI floor and never allows a negative medical deduction.

Publication 502 rules determine which patients, services, insurance premiums, transportation, and timing are eligible. The calculator does not make those eligibility decisions.

Only unreimbursed eligible expenses above 7.5% of adjusted gross income enter itemized deductions. At $100,000 of AGI, the floor is $7,500, so $10,000 of unreimbursed eligible expenses produces a $2,500 modeled deduction.

Expenses equal to or below the floor produce zero, while reimbursements cannot exceed the entered paid amount. No intermediate dollar rounding is applied.

Schedule A generally permits a choice between eligible state and local income taxes and general sales taxes. The two amounts cannot be added together, so TaxArith automatically selects the larger submitted figure.

The results identify the selected option. The user must determine the sales-tax amount because this MVP does not implement the IRS optional sales-tax tables.

The 2026 base SALT cap is $40,400 for Single, MFJ, HOH, and QSS, or $20,200 for MFS. Eligible selected income or sales tax, real estate tax, and personal property tax share this single cap.

The allowed amount is the smaller of modeled SALT paid and the applicable cap. An amount not included under this model is not described as permanently lost because filed-return treatment depends on the law and the taxpayer's facts.

The cap decreases by 30% of modeled SALT MAGI above $505,000, or above $252,500 for MFS. It cannot fall below $10,000, or $5,000 for MFS.

This MVP sets modeled SALT MAGI equal to AGI. Official MAGI can require additions for Form 2555, Form 4563, or excluded Puerto Rico income, which are not supported here.

Eligible state and local real estate taxes and personal property taxes are added to the selected income-or-sales-tax figure before the SALT cap. Merely paying a charge to a local government does not automatically make it deductible.

Assessments for local benefits, business taxes, foreign property tax, and other special categories can require different treatment that this calculator does not determine.

Enter mortgage interest and points only after determining the deductible amount under Publication 936 and other applicable guidance. Qualified-home rules, debt dates, acquisition-debt limits, average balances, and points timing can all matter.

TaxArith deliberately avoids a shortcut based only on the current mortgage balance. It does not calculate acquisition indebtedness, grandfathered debt, or amortize points.

Interest is not deductible merely because a home secures the loan. The use of proceeds and acquisition-debt rules can determine whether home-equity loan or line-of-credit interest qualifies.

Enter only the amount you have already determined deductible. The calculator does not trace loan proceeds or allocate mixed personal and qualified uses.

The form accepts a mortgage-insurance-premium amount already determined deductible for 2026. Any statutory eligibility, acquisition-debt relationship, and AGI phaseout must be applied before entry.

This model does not calculate the mortgage-insurance phaseout or decide whether a payment is qualified mortgage insurance.

Investment interest can be limited by net investment income and elections reflected through Form 4952. Enter the amount already allowable after those rules.

TaxArith does not classify investment expenses, calculate net investment income for this purpose, apply a qualified-dividend or capital-gain election, or prepare Form 4952.

For 2026, this model subtracts 0.5% of AGI from total eligible cash and noncash contributions before including charity in itemized deductions. Amounts at or below the floor produce zero in the itemized path.

The amount below the floor is shown as not included, not as a modeled carryover. Percentage limits and lawful carryover treatment may further change the filed-return amount.

Cash and noncash contributions combine for the itemized 0.5% floor, but only eligible cash can support the separate non-itemizer deduction. The form therefore preserves the two categories independently.

The user must determine organization eligibility, substantiation, property value, percentage limits, and carryovers. TaxArith does not appraise donated property or prepare Form 8283.

Enter only a deductible disaster casualty and theft loss already calculated from Form 4684. Federal disaster declarations, personal-use property limits, reimbursements, insurance claims, and timing can affect that amount.

The entered amount passes into the itemized subtotal without another casualty floor because the form assumes Form 4684 work is complete. TaxArith does not prepare that form.

The modeled 2026 deduction is the lesser of gambling winnings or 90% of entered gambling losses. Winnings are assumed already included in AGI and are not added a second time.

Gambling winnings still must be reported separately under applicable rules. The calculator does not verify sessions, records, professional-gambler treatment, or whether a particular loss is eligible.

The other-itemized field is for an already eligible Schedule A amount after its own special limitations. It should not repeat medical, SALT, interest, charity, casualty, or gambling amounts entered elsewhere.

This field cannot turn an expressly limited category into an unrestricted deduction. Keep supporting records showing what the amount represents and how it was determined.

After every category limit, the calculator measures income before either deduction path against $640,600 for Single/HOH, $768,700 for MFJ/QSS, or $384,350 for MFS. The reduction is 5.4% of the smaller of the itemized subtotal or excess income.

The limitation never applies to the standard deduction or non-itemizer charity deduction. Break-even uses the same aggregate function because an additional itemized dollar can itself be affected by this reduction.

A larger deduction can produce no additional modeled tax savings when both paths already reduce taxable income to zero or when other tax mechanics leave the two regular-tax results equal. Recommendation therefore follows tax, not deduction size alone.

Multiplying the deduction difference by one marginal rate is unreliable across progressive brackets and preferential-income stacking. TaxArith calculates both complete scenarios instead.

Qualified dividends and net long-term capital gain remain included in AGI, but eligible amounts use the shared 0%, 15%, and 20% preferential stack after deductions determine taxable income. They are never added to AGI again.

Each scenario limits preferential taxable income to total taxable income and uses the same progressive ordinary brackets, preferential thresholds, and regular-tax comparison safeguard.

Common records include medical invoices and reimbursement statements, state and local tax records, property-tax bills, Forms 1098, charitable acknowledgments, appraisal and Form 8283 support, disaster records, gambling statements and logs, and Form 4952 workpapers.

Record requirements depend on the category and facts. This calculator stores nothing, verifies no document, and does not prepare Schedule A or any supporting form.

The 2026 standard-deduction amounts, dependent formula, age-and-blindness additions, federal tax brackets, and related inflation-adjusted amounts were verified on August 11, 2026 using IRS Revenue Procedure 2025-32 as published in Internal Revenue Bulletin 2025-45. The 2026 medical-expense floor, charitable-contribution floor, non-itemizer charitable deduction, overall itemized-deduction limitation, gambling-loss limitation, SALT amounts, and other current-year rules were reviewed using IRS Publication 505 for 2026 and current IRS guidance.

The available 2026 Schedule A was reviewed as an IRS draft and was not treated as a final filing form. Rules and forms can change, state tax rules can differ, and users should confirm current guidance before filing.