IRS and SSA sources and calculation methods

Focused federal calculators

All five tools use the ordinary income brackets in IRS Revenue Procedure 2025-32. They calculate each taxable slice at its bracket rate; they do not apply the highest rate to all income.

• Bracket headroom subtracts taxable income from the current bracket ceiling. At an exact boundary, the next dollar enters the next bracket; the top bracket has no ceiling.
• Extra income tax subtracts tax on current taxable income from tax after adding ordinary income. It excludes payroll taxes and credit changes.
• Deduction savings compares tax before and after an additional eligible deduction, capped at entered taxable income. It does not determine deduction eligibility.
• Effective tax rate divides ordinary income tax by income before the entered deduction. The marginal rate describes the next taxable dollar, including at an exact bracket boundary. No deduction is applied beyond the amount entered.
• Child tax credit uses separate modified AGI, earned income, and tax liability inputs. The $2,200 child credit phases out by $50 for each $1,000 (or fraction) above $400,000 for joint filers or $200,000 for other statuses. Refundable credit is limited by remaining credit, $1,700 per child, and 15% of earned income above $2,500. The three-or-more-child payroll alternative and other-dependent credit are excluded.

Bracket, extra-income, deduction, and effective-rate tools omit credits, preferential capital gains rates, AMT, payroll and state taxes. Enter income and deductions only once. Eligibility requirements still apply to child credits; the tool does not determine them.

Bonus withholding and take-home pay

The bonus tax calculator models the eligible supplemental percentage method: 22% through $1 million of annual supplemental wages from the employer and commonly controlled businesses, then 37%. IRS Publication 15 (2026), sections 7 and 9, supplies these rates, 6.2% employee Social Security through $184,500, 1.45% Medicare and 0.9% Additional Medicare withholding above $200,000 employer wages.

Separate Social Security and Medicare wage histories determine payroll deductions. The annual income-tax comparison uses 2026 brackets and holds the entered deduction constant. Withholding is a prepayment; this difference does not predict a refund. Aggregate payroll methods, state taxes, benefits, credit changes and final payroll reconciliation are excluded. See IRS Publication 505 for withholding guidance.

1099 income and self-employment tax

The self-employment tax calculator uses the regular Schedule SE method: 92.35% of net profit, a $400 adjusted-net-earnings threshold, 12.4% Social Security within the owner's remaining $184,500 wage base, and 2.9% Medicare. Half of regular SE tax is deductible for income tax. Form 8959 instructions govern 0.9% Additional Medicare Tax and coordination with Medicare wages; joint returns combine spouses' Medicare wages, while each person's Social Security cap stays separate.

The 1099 tax calculator adds ordinary income tax, optionally applies a supported active-business QBI deduction, and subtracts annual payments. Its reserve percentage measures the tax increase from the business relative to net profit. It excludes credits, state taxes, capital gains, losses, spouse self-employment and other self-employed adjustments. It does not calculate quarterly safe harbors, installment dates or penalties.

Revenue Procedure 2025-32 and the IRS QBI overview supply the 2026 QBI thresholds and $400 minimum for eligible active-business QBI of at least $1,000. The optional single-business calculation stops above its supported taxable-income threshold. Eligibility and exclusions are described on the 1099 page. SE and Additional Medicare methods reference published 2025 instructions with verified 2026 indexed amounts.

Qualified overtime deduction

The overtime tax calculator uses established FLSA-required premium pay, subject to 2026 W-2 code TT reporting, an eligible SSN, and joint filing for married taxpayers. Annual caps are $12,500, or $25,000 jointly. Above $150,000 MAGI ($300,000 jointly), reduce the deduction by $100 per complete $1,000 of excess MAGI, rounded down under Schedule 1-A Part III (published 2025 form).

The IRS August 2026 overtime FAQ explains qualifying premiums, reporting, withholding and eligibility. The tool compares ordinary income tax before and after the allowed deduction; payroll taxes still apply. It does not determine FLSA eligibility, calculate a paycheck, or model credits and other deduction interactions.

IRA required minimum distributions

The RMD calculator divides adjusted December 31, 2025 balances by the age-based Uniform Lifetime Table factor in IRS Publication 590-B, Appendix B. It supports living original owners of traditional, SEP and SIMPLE IRAs, subtracts eligible distributions credited to 2026, and rounds upward to cents as a display convention.

IRS RMD FAQs explain deadlines and IRA aggregation. The tool stops for inherited accounts, employer plans, and a sole-beneficiary spouse more than 10 years younger; those cases require different rules or tables. Original-owner Roth IRAs have no lifetime RMD. It estimates a distribution requirement, not tax or a penalty; confirm special balance adjustments and distributions with the custodian.

Social Security

SSA 2026 COLA fact sheet gives the official 2.8% increase. The calculator also offers historical 2025 (2.5%) and 2024 (3.2%) rates; see SSA COLA history. The adjustable scenario is hypothetical and is not an official 2027 rate or sourced forecast.

SSA primary insurance amount formula and SSA bend points define the 2026 PIA sketch: AIME is first rounded down to a whole dollar, then the formula applies 90% of the first $1,286 of AIME, 32% through $7,749, and 15% above, rounded down to a dime.

The PIA sketch is for someone reaching age 62 in 2026, before later COLAs and claiming-age adjustments. COLA results apply a percentage to gross monthly benefits; actual SSA awards can differ due to rounding and individual adjustments. Medicare is entered separately and is not forecast here.