US Payroll Tax Engine: proof of concept

Gross-to-net tax calculation on Cloudflare Workers + D1, with effective-dated, versioned regulatory snapshots.

Demo regulatory data only. Values are not certified by a payroll-tax expert and must not be used for real payroll.

Scenario

API token

Pay date

Frequency

Gross wages

of which supplemental

401(k) deferral

Section 125

Filing status

W-4 Step 3 credits

W-4 Step 2 (multiple jobs)

Work state

Work locality

Residence state

Residence locality

YTD Social Security wages

YTD Medicare wages

YTD FUTA wages

Pick a scenario and press Calculate.