Bonus Tax Calculator: Estimate 2026 Withholding

What this 2026 bonus calculator estimates

This page models a separately stated employee bonus under the federal supplemental-wage percentage method described in IRS Publication 15. It estimates federal income-tax withholding, employee Social Security, basic Medicare, Additional Medicare withholding, and the amount left before state and local withholding. It is not a tax-return calculation, legal advice, payroll filing, or a guarantee that a paystub will match.

The percentage-method eligibility confirmation matters: the bonus must be separately identified, and federal income tax must have been withheld from regular wages in the current or immediately prior calendar year. Combined regular and bonus pay, an employer's aggregate method, non-FICA wages, railroad pay, contractor income, stock compensation, deductions, benefits, and employer-side taxes need different facts or rules.

Why there are three YTD wage fields

The three totals answer different legal questions and must not be replaced with one generic salary number. Prior supplemental wages controls how much of this bonus remains in the 22% slice before annual supplemental wages exceed $1 million. Social Security-taxable wages YTD controls how much remains below the 2026 $184,500 wage base. Medicare-taxable wages YTD controls the employer's $200,000 Additional Medicare withholding trigger.

For the $1 million federal test, prior supplemental wages include payments from common-control businesses where Publication 15 requires aggregation. For Social Security and Medicare, use the paying employer's payroll YTD record unless payroll confirms that successor-employer or common-paymaster treatment applies. If you do not know these totals, asking payroll is more honest than guessing from annual salary.

22% and 37% apply to slices, not the whole bonus

Let B be this bonus and P be prior annual supplemental wages from the employer and common-control businesses. The 22% slice is min(B, max(0, $1,000,000 − P)). Only the remaining slice uses 37%. For a $10,000 bonus after $995,000 of prior supplemental wages, the receipt shows $5,000 × 22% = $1,100 and $5,000 × 37% = $1,850, for $2,950 of federal supplemental withholding—not a claim that $2,950 is final income tax.

Social Security and Medicare thresholds

Employee Social Security withholding is 6.2% of the part of the bonus that still fits under the 2026 $184,500 contribution and benefit base. Basic Medicare withholding is 1.45% of the full covered bonus. Additional Medicare withholding is 0.9% of the part that pushes wages paid by the employer above $200,000, following IRS Topic 751.

The $200,000 amount is an employer withholding trigger, not every individual's final liability threshold. IRS Publication 505 explains that the final Additional Medicare liability threshold varies with filing status, which is another reason this result cannot be called final tax owed.

State and local withholding is bounded honestly

This tool does not infer a state from your location and does not maintain a 50-state payroll matrix. The Texas option uses the Texas Comptroller's official statement that Texas has no individual state income tax; it does not claim that every local or payroll item is zero. Everywhere else, leave the amount “unknown / not included” or enter a state/local withholding amount yourself. A user-entered amount is subtracted and labelled as your input, not a ToolNeko tax calculation.

Rounding, export, offline use and privacy

Inputs accept dollars and cents without commas or currency symbols. The calculator parses integer cents, applies each displayed rate with rational arithmetic, and rounds each component half up to the nearest cent before adding the receipt. Employer payroll software can use a different permitted rounding convention.

The current receipt and UTF-8 CSV include the tax year, input labels, rate slices, results, state/local status, source-check date and estimate warning. Changing any input clears the previous result and locks its exports. Once this page's static code is loaded, a new calculation, copy and CSV export continue without a network connection. Amounts, eligibility choices and results are not placed in URLs or browser storage and are not sent to a payroll service or analytics.