Gross-Up Payroll Calculator 2026

What a gross-up payroll calculator does

A gross-up starts with a promised net payment and estimates the taxable gross wages needed to fund both the payment and its withholding. For example, an employer may promise a $1,000 net bonus. Paying $1,000 in gross wages would deliver less than that promise because withholding comes out of the check. The gross-up increases gross pay until the modeled deductions leave the requested net amount.

Use bonus mode for a separately identified supplemental payment when the flat federal method is available. Use regular mode for a paycheck calculated from the W-4 percentage method. Add year-to-date wages before this payment so Social Security and Additional Medicare withholding reflect the payment’s position in the year. State and local withholding are entered as flat rates, rather than inferred from a state income tax bracket.

Net-to-gross formula when every rate stays constant

If all deductions are flat percentages and there are no thresholds inside the payment, gross pay = (desired net pay + fixed after-tax deductions) ÷ (1 − combined withholding rate). The combined rate includes federal withholding, employee FICA, and entered state or local withholding. A fixed after-tax deduction belongs in the numerator because it takes the same dollar amount out of the payment.

For a $1,000 net bonus below the wage caps, with 22% federal withholding and 7.65% employee FICA, the constant-rate calculation is $1,000 ÷ 0.7035 = approximately $1,421.46. The calculator rounds individual withholding lines to cents and finds a cent-level gross payment that delivers at least the requested net.

Multiplying $1,000 by 1.2965 is insufficient: the added wages themselves also have withholding. A net-to-gross calculation must fund that second layer. Once a payment crosses a wage cap or federal supplemental threshold, use the full calculation rather than a single-rate formula.

Worked examples: the same $1,000 net bonus in different circumstances

All examples use a separately paid bonus, eligible 22% federal withholding, no earlier supplemental wages, no fixed deductions and 2026 federal figures. State withholding in the third row is a hypothetical flat 5% input; it is not a claim about any state's actual payroll method.

Choosing bonus withholding or regular paycheck withholding

IRS Publication 15 describes the optional 22% supplemental method and the mandatory 37% rate on supplemental wages above $1 million in a calendar year. The optional method generally requires income tax to have been withheld from regular wages in the current or preceding year. The employer may instead use an aggregate method; this calculator does not implement that alternative.

Regular paycheck mode reads your supplied W-4 entries and pay frequency. Its gross result is treated as federal taxable wages for that pay period. A higher Step 3 credit can lower the gross needed, while extra Step 4(c) withholding can raise it. The regular calculation assumes no pre-tax deduction changing the relationship between gross wages and federal taxable wages.

Year-to-date wages can change the gross-up inside a payment

Social Security withholding stops at $184,500 of covered wages in 2026. If prior wages are $184,000, only the first $500 of this payment is subject to its 6.2% employee share. Medicare continues without a wage cap. Employer Additional Medicare withholding begins above $200,000 regardless of filing status.

The calculator splits the payment at those thresholds and rounds the withholding lines. Enter covered wages before this payment, not projected annual income including the gross-up. For supplemental wages, the separate year-to-date field determines how much of the payment remains below the $1 million threshold.

A grossed-up bonus does not fix the final tax on your return

The result guarantees only the modeled payment net. Income tax withholding is a prepayment; the eventual tax calculation considers total annual income, filing status, deductions and credits. A recipient can still owe tax or receive a refund after a correctly grossed-up bonus.

Before promising a net amount, record which deductions the promise covers. A federal-only gross-up and a gross-up including employee state contributions have different results. The calculator’s breakdown lets you compare the agreement with the actual payroll lines rather than assuming every deduction was covered.

What an employer still needs to budget

Gross wages are not the employer’s complete cost. Employer FICA, unemployment taxes and other employer expenses can apply in addition to the employee withholding funded here. Those costs do not appear in the employee net equation. This tool therefore reports gross wages needed, not an all-in hiring or payroll cost.

State contribution caps, state withholding tables, local jurisdiction rules, pre-tax benefits, aggregate bonus withholding and noncash taxable fringe-benefit valuation are outside this calculation. If those items matter, reproduce the payroll rules applicable to the payment before using the gross result in payroll.