HR Software That Handles US State Taxes

The short answer

HR software that handles US state taxes must calculate the correct rules for each employee's state — graduated brackets, a flat rate, or no income tax at all — on top of federal tax. Mellow does this for eight launch states including California, New York, Texas, and Florida, with state tax included in its payroll engine.

Why US state tax is the hard part

US payroll has two layers. The federal layer — income tax, FICA, FUTA — is the same for every employer. The state layer is where software succeeds or fails, because the states do not agree.

- Some states — Texas, Florida, Washington — have no state income tax.

- Some — Illinois, Massachusetts — apply a single flat rate.

- Some — California, New Jersey — use graduated brackets, and California's top rate reaches 13.3%.

- New York adds a further layer: residents of New York City pay an additional city tax.

Software that handles US state taxes properly has to know which of these applies to each employee and calculate accordingly.

How Mellow handles US state taxes

Mellow's payroll engine calculates US federal tax — the seven income-tax brackets, FICA, and FUTA — and then applies state tax for eight launch states: California, New York, Texas, Florida, Illinois, Washington, Massachusetts, and New Jersey. Together these cover a large share of US employment.

For California it applies graduated brackets and state disability insurance. For New York it applies state tax and, for New York City residents, the additional city tax. For Texas, Florida, and Washington it correctly applies no state income tax. For Illinois and Massachusetts it applies the flat rate.

State tax is part of the payroll engine, not an add-on. The payslip shows the federal, state, and FICA breakdown clearly.

The honest scope

Mellow currently covers eight US states. They were chosen for coverage, but they are not all fifty — if you employ people in a state outside the eight, Mellow does not yet calculate that state's tax. More states are added by configuration over time.

Mellow also does not file with the IRS or state agencies for you; it calculates accurately and guides you through Form 941 and your state returns.

For US payroll where state tax is handled as a core capability, see Mellow pricing.