How to Gross Up a Paycheck: Formula, Limits, and Employer Cost

To gross up a paycheck, add together every tax rate that will apply to the payment, subtract that combined rate from 1, and divide the net amount you want the employee to receive by the result. The quotient is the gross figure you enter into payroll. Employers use this method whenever they’ve promised a specific take-home dollar amount — a $5,000 bonus, a relocation check, a signing incentive — and need the paycheck to land at that number after withholding.

Gather the Tax Rates First

The formula only works if you’ve identified every rate that will reduce the payment. For supplemental wages such as bonuses, commissions, and relocation payments, federal income tax withholding is a flat 22 percent, provided the employee’s total supplemental wages for the year stay at or below one million dollars.¹ That flat rate applies regardless of what the employee put on Form W-4.

Two payroll taxes apply on top of federal withholding:

Social Security (OASDI) at 6.2 percent of wages, up to the 2026 wage base of $184,500.²³
Medicare at 1.45 percent of all wages, with no cap.²

If your state or locality taxes wages, add that rate too. Some states publish a flat supplemental withholding rate, roughly 4 to 12 percent depending on the state; others require you to use the employee’s regular withholding rate. Check your state’s department of revenue.

One boundary to note: the 22-percent flat rate is available only when income tax was withheld from the employee’s regular wages during the current or prior calendar year. If it wasn’t, you calculate federal withholding using the employee’s Form W-4 instead.¹

Convert every rate to a decimal (22 percent becomes 0.22) before you plug anything in.

Run the Formula

Three steps: combine the rates, find the take-home share of each dollar, divide.

Step 1. Add the applicable tax rates. For an employee subject to the 22-percent supplemental rate, 6.2 percent Social Security, and 1.45 percent Medicare, the combined rate is 29.65 percent (0.2965). Add a 5-percent state tax and the combined rate becomes 34.65 percent (0.3465).

Step 2. Subtract the combined rate from 1. Using the federal-only figures: 1.0 − 0.2965 = 0.7035. That decimal is the share of each gross dollar the employee keeps.

Step 3. Divide the desired net by that result. To deliver exactly $5,000 in take-home pay:

$5,000 ÷ 0.7035 = $7,107.32

Enter $7,107.32 as the gross into payroll. To verify:

Federal income tax: $7,107.32 × 0.22 = $1,563.61
Social Security: $7,107.32 × 0.062 = $440.65
Medicare: $7,107.32 × 0.0145 = $103.06
Total withheld: $2,107.32
Net pay: $7,107.32 − $2,107.32 = $5,000.00

Add a state rate and the divisor shrinks, so the gross climbs. With 5-percent state tax layered in, the divisor drops to 0.6535 and the gross-up for the same $5,000 net becomes $7,653.41.

When the Simple Formula Breaks

The single-divisor version works cleanly until the payment crosses one of three thresholds. Past any of them, you split the calculation.

The Social Security Wage Base

Social Security withholding stops once the employee’s cumulative wages for the year hit $184,500 in 2026.¹ If an employee has already earned $180,000 before a grossed-up bonus, only the first $4,500 of the gross-up is subject to the 6.2 percent. The rest is taxed only at federal income tax plus Medicare (and any state rate). You can’t use one flat divisor in that situation — split the calculation at the wage-base ceiling, or let payroll software that handles the cap do it for you.

Supplemental Wages Over One Million Dollars

Once an employee’s total supplemental wages for the calendar year exceed one million dollars, the federal withholding rate on the excess rises from 22 percent to 37 percent.¹ A gross-up that straddles the line needs two separate calculations: one at 22 percent up to the million-dollar mark, one at 37 percent for everything above.

Additional Medicare Tax

Employers must withhold an extra 0.9 percent Medicare tax on wages above $200,000 in a calendar year, regardless of the employee’s filing status. If the grossed-up payment pushes cumulative wages past that mark, use 2.35 percent (1.45 percent plus 0.9 percent) in the formula for the portion above $200,000. There is no employer match on the Additional Medicare Tax; only the employee owes it.⁴

What It Actually Costs the Employer

A gross-up costs more than the difference between the promised net and the calculated gross. The employer also owes its own payroll taxes on the higher gross amount:

Employer Social Security: 6.2 percent of the grossed-up wages, up to the $184,500 wage base.⁵
Employer Medicare: 1.45 percent of the grossed-up wages, no cap.⁵
Federal Unemployment (FUTA): 6 percent on the first $7,000 of each employee’s annual wages, reduced to an effective 0.6 percent after the standard 5.4-percent credit for state unemployment tax payments. Most employees have already blown past the $7,000 FUTA base before a mid-year bonus, so this rarely applies to gross-ups.⁶

Back to the running example. Grossing up a $5,000 net bonus to $7,107.32 costs the employer an extra $440.65 in Social Security match and $103.06 in Medicare match on top of the $2,107.32 already absorbed through the gross-up itself. Delivering that $5,000 net actually runs the company about $7,651.

Entering and Reporting the Payment

Enter the grossed-up figure — $7,107.32 in the example — as the gross pay for the payment. Configure withholding using the same rates you used in the formula so the calculated net matches your target. Most payroll platforms include a gross-up function that runs the math once you input the desired net and the applicable rates.

Grossed-up wages report like any other taxable wages; the IRS does not require a separate line identifying a payment as a gross-up. On Form 941, include the grossed-up wages and all withheld taxes in the quarter you paid them.⁷ On the annual Form W-2, the full grossed-up amount goes in Box 1, Social Security wages in Box 3, Social Security tax withheld in Box 4, Medicare wages in Box 5, and Medicare tax withheld in Box 6.⁸ The employee’s W-2 shows the full taxable gross, not the net you promised, which can shift the employee’s own tax return if their actual marginal rate differs from the flat 22 percent used in the gross-up.

1
Internal Revenue Service. Publication 15 (2026), (Circular E), Employer’s Tax Guide
2
Office of the Law Revision Counsel. 26 USC 3101 – Rate of Tax
3
Social Security Administration. Contribution and Benefit Base
4
Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
5
Internal Revenue Service. Understanding Employment Taxes
6
Office of the Law Revision Counsel. 26 USC 3301 – Rate of Tax
7
Internal Revenue Service. Instructions for Form 941 (Rev. March 2026)
8
Office of the Law Revision Counsel. 26 USC 6051 – Receipts for Employees