Bonus / supplemental tax withholding API

Estimate withholding on a bonus using the US supplemental flat-rate method: 22% federal (IRS flat rate) + optional 7.65% FICA (6.2% SS + 1.45% Medicare) + a state rate, returning net bonus and effective rate. Deterministic withholding math. Answers 'how much tax on a $10k bonus','what's my net bonus','supplemental withholding rate'.

Price$0.01per request

MethodPOST

Route/v1/calc/hr-bonus-tax-withholding

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

hrpayrollbonustaxwithholdingcalcficasupplemental

API URLhttps://x402.hexl.dev/v1/calc/hr-bonus-tax-withholding

Integration docs

Example request

{
  "bonusAmount": 10000
}

Example response

{
  "bonusAmount": 10000,
  "federalRate": 0.22,
  "stateRate": 0,
  "ficaRate": 0.0765,
  "includeFica": true,
  "federalTax": 2200,
  "stateTax": 0,
  "ficaTax": 765,
  "totalWithheld": 2965,
  "netBonus": 7035,
  "effectiveWithholdingRate": 0.2965
}

Input schema

{
  "type": "object",
  "required": [
    "bonusAmount"
  ],
  "properties": {
    "bonusAmount": {
      "type": "number",
      "description": "Bonus amount in dollars",
      "examples": [
        10000
      ]
    },
    "federalRate": {
      "type": "number",
      "default": 0.22,
      "examples": [
        0.22
      ]
    },
    "stateRate": {
      "type": "number",
      "default": 0,
      "examples": [
        0
      ]
    },
    "includeFica": {
      "type": "boolean",
      "default": true
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}