South Carolina Bonus Pay Tax Calculator

2026 South Carolina bonus withholding

South Carolina Bonus Pay Tax Calculator

Estimate a South Carolina employee's net bonus with the published 2026 payroll withholding methods, federal supplemental-wage rules, FICA thresholds, Act 110 transition guidance, employer costs, and net-to-gross planning.

Calculate a South Carolina paycheck Explore TimeTrex payroll

Act 110 transition - verify SCDOR before a production payroll run

Act 110 applies a new 1.99% / 5.21% annual individual income-tax schedule for tax years beginning after 2025 and directs SCDOR to adjust withholding tables. As last verified July 20, 2026, SCDOR's live withholding hub still linked the 2026 WH-1603 and WH-1603F materials issued before the Act, while SCDOR said further guidance would follow. This calculator keeps those published payroll methods visible and editable; it does not treat 5.21% as a universal bonus-withholding rate.

Bonus inputs

Use gross-to-net for a planned bonus or net-to-gross when a take-home amount was promised.

Gross bonus amount Enter the taxable bonus to be paid.

Supplemental pay type

Federal withholding method

Payment presentation Payment presentation controls federal method eligibility and the South Carolina automatic choice. Auto uses the 6.00% estimate only for a separate payment and WH-1603F combined/difference logic when paid with regular wages.

Regular wages had federal income tax withheld

The optional 22% federal flat method generally depends on regular wages having had income tax withheld in the current or prior year.

Pay frequency

YTD Social Security wages from this employer Used only for the 2026 $184,500 Social Security wage-base check.

YTD Medicare wages from this employer Used for the employer's $200,000 Additional Medicare withholding threshold.

YTD supplemental wages before bonus Include supplemental wages paid in 2026 by this employer and businesses under common control for the $1 million federal test.

Regular wages for this pay period Used for aggregate withholding comparisons.

Federal W-4 settings

Federal filing status

Use higher W-4 Step 2 checkbox tables

Annual credits from W-4 Step 3

Annual other income from W-4 Step 4(a)

Annual deductions from W-4 Step 4(b)

Extra federal withholding per regular check

Extra federal withholding on this bonus

South Carolina withholding settings

South Carolina withholding profile South Carolina generally withholds on wages for services performed in the state. A missing SC W-4 is modeled with zero allowances; a claimed exemption must be valid for 2026.

South Carolina income-tax withholding applies

The profile sets this control, but it remains editable for documented payroll treatment.

South Carolina bonus withholding method Automatic uses 6.00% only when paid separately and the official annualized formula when the bonus is paid with regular wages.

Custom South Carolina payroll rate Used only for Custom payroll percentage. Do not enter 5.21% merely because it is Act 110's top annual rate; use the employer's current SCDOR/payroll instruction.

South Carolina-taxable bonus percentage Use 100% for fully South Carolina-taxable wages. Enter a supportable South Carolina-source allocation for multistate services.

Regular South Carolina-taxable wages for this period Used by the combined/difference method. The calculator determines WH-1603F withholding on regular wages plus the allocated bonus, then subtracts regular-pay withholding.

SC W-4 allowances WH-1603F allows $5,000 per allowance. With one or more allowances, the standard deduction is 10% of annual gross wages up to $7,500; zero allowances means no standard deduction.

Additional South Carolina withholding on this payment Optional additional amount requested on SC W-4 line 6 or otherwise supported by payroll records.

Employer cost estimate settings

2026 South Carolina UI total-rate preset Presets include the 0.060% DACA assessment. Experienced employers should enter the total rate assigned by South Carolina DEW.

YTD South Carolina UI-taxable wages before bonus Used only for employer-side unemployment tax.

South Carolina UI wage base The official 2026 taxable wage base is the first $14,000 paid to each covered employee.

South Carolina UI employer total rate The selected 1.060% new-employer rate includes 1.000% base plus 0.060% DACA. Enter the assigned total rate when known.

South Carolina UI-covered bonus percentage Bonuses are included in South Carolina UI wages for covered employment. UI localization can differ from income-tax sourcing and changes employer cost only.

YTD FUTA wages before bonus Used only for the employer-side $7,000 FUTA wage-base estimate.

Estimated net FUTA rate Default assumes the full 5.4% state credit. Final 2026 credit-reduction status is determined after November 10.

Estimated net bonus

Federal flat method with South Carolina's published 2026 payroll estimate.

Net bonus $0.00 Tax withholding estimate updates as inputs change.

Gross bonus $0.00

Total withheld $0.00

Effective withholding 0.00%

Employer cost estimate $0.00

Withholding line	Amount

Method comparison

Method	Net bonus	Total withheld

What this calculator includes

Transparent South Carolina methods

Use the published 6.00% separate-payment estimate, the WH-1603F combined/difference formula, automatic timing logic, or a documented custom payroll rate.

Federal supplemental methods

Model the optional 22% method, mandatory 37% treatment only above $1 million, and the aggregate method using 2026 Publication 15-T.

Separate employee and employer taxes

Test Social Security, Additional Medicare, South Carolina UI, and FUTA against separate year-to-date wage inputs without reducing take-home by employer-only taxes.

This is a 2026 withholding estimate for an ordinary taxable cash bonus paid to a W-2 employee. Act 110 changes annual South Carolina liability but does not, by itself, make 5.21% a bonus-check withholding instruction. Pretax benefits, retirement deferrals, wage exclusions, sourcing, successor-employer rules, common-control supplemental payments, payroll rounding, updated SCDOR tables, and employee-specific facts can change the paycheck.

South Carolina bonus withholding FAQ

Does South Carolina use a flat bonus withholding rate?

A January 2026 federal payroll implementation notice reports a 6.00% South Carolina flat supplemental rate. This calculator treats it as a published payroll estimate for a separate payment, not as final tax liability.

How does the combined South Carolina method work?

The calculator applies WH-1603F to regular South Carolina wages plus the allocated bonus, rounds the period result, and subtracts the rounded withholding on regular wages alone.

Does Act 110 make every bonus subject to 5.21%?

No. Act 110 changes the annual 2026 individual income-tax calculation and requires SCDOR to adjust withholding tables. The 5.21% rate is not a universal bonus-check instruction.

What if the employee has no SC W-4?

The missing-form preset uses zero allowances. Under the published 2026 formula, zero allowances also means no standard deduction in the withholding calculation.

Can an SC W-4 exemption remove withholding?

A valid 2026 exemption can result in no South Carolina withholding. The employer should retain the signed form and follow any contrary SCDOR instruction.

When can an employer use federal 22% withholding?

It is optional for an eligible separately paid or separately identified supplemental amount when federal income tax was withheld from regular wages in the current or immediately preceding year.

Does South Carolina unemployment insurance reduce the bonus?

No. South Carolina UI is employer-financed. The employer-cost estimate uses the $14,000 wage base and an editable assigned total rate.

Can this calculator gross up a promised net bonus?

Yes. Net-to-gross mode solves across federal method rules, the selected South Carolina method, Social Security, Medicare, and Additional Medicare thresholds.

Research sources

Primary official material was checked on July 20, 2026. Because Act 110 directs SCDOR to revise withholding tables, recheck the live hub before every production implementation.

South Carolina Department of RevenueLive withholding hub and 2026 publications

South Carolina Department of RevenueWH-1603F: 2026 withholding formula

South Carolina Department of RevenueWH-1603: 2026 withholding tables

South Carolina Department of Revenue2026 SC W-4

South Carolina Department of RevenueAct 110 / H.4216 implementation notice

South Carolina General AssemblyAct 110 text, rates, SCIAD, and withholding-table directive

U.S. DOI Interior Business Center2026 South Carolina 6.00% supplemental implementation

South Carolina DEW2026 UI rates, DACA, and $14,000 wage base

South Carolina DEWBonuses included in UI wages

IRSPublication 15 (Circular E), 2026

IRSPublication 15-T, 2026

IRSFUTA credit-reduction timing

Social Security Administration2026 contribution and benefit base

TimeTrexSouth Carolina payroll tax calculator (CTA only)

Move from a bonus estimate to a complete South Carolina paycheck

Need the full paycheck picture? Estimate regular wages, federal withholding, South Carolina income tax, Social Security, and Medicare with TimeTrex's free South Carolina Payroll Tax Calculator, or connect approved earnings and payroll records in one workflow.

Calculate a South Carolina paycheck Explore TimeTrex payroll

Disclaimer: This calculator provides estimated tax withholdings for informational and planning purposes only and does not constitute formal tax, legal, or payroll advice. Actual paycheck withholdings and net pay may vary based on specific employee elections, pre-tax deductions, individual W-4 settings, year-to-date earnings caps, and official payroll system calculations. Because South Carolina Act 110 updates annual individual tax schedules and directs the South Carolina Department of Revenue (SCDOR) to revise withholding guidance, users should verify current SCDOR tables and consult a certified tax professional or payroll specialist prior to executing production payroll runs.

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Disclaimer: The content provided on this webpage is for informational purposes only and is not intended to be a substitute for professional advice. While we strive to ensure the accuracy and timeliness of the information presented here, the details may change over time or vary in different jurisdictions. Therefore, we do not guarantee the completeness, reliability, or absolute accuracy of this information. The information on this page should not be used as a basis for making legal, financial, or any other key decisions. We strongly advise consulting with a qualified professional or expert in the relevant field for specific advice, guidance, or services. By using this webpage, you acknowledge that the information is offered “as is” and that we are not liable for any errors, omissions, or inaccuracies in the content, nor for any actions taken based on the information provided. We shall not be held liable for any direct, indirect, incidental, consequential, or punitive damages arising out of your access to, use of, or reliance on any content on this page.

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South Carolina Bonus Pay Tax Calculator