Roth vs Traditional break-even API

Compare after-tax terminal values of an equal gross contribution: Roth (post-tax in, tax-free out) vs Traditional (pre-tax in, taxed at the retirement rate out), compounding at the annual return over N years, returning both terminal values, the difference, and a recommendation. Estimate only; ignores limits/RMDs. Answers 'Roth or Traditional 401k','which IRA wins if my retirement rate is lower','after-tax value of each','break-even tax rate'.

Price$0.01per request

MethodPOST

Route/v1/calc/tax-roth-vs-traditional

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

taxrothtraditionalira401kretirementbreak-evencalc

API URLhttps://x402.hexl.dev/v1/calc/tax-roth-vs-traditional

Integration docs

Example request

{
  "contribution": 10000,
  "years": 30,
  "annualReturn": 0.07,
  "currentTaxRate": 0.24,
  "retirementTaxRate": 0.22
}

Example response

{
  "contribution": 10000,
  "years": 30,
  "annualReturn": 0.07,
  "currentTaxRate": 0.24,
  "retirementTaxRate": 0.22,
  "roth": {
    "afterTaxContribution": 7600,
    "terminalAfterTax": 57853.14
  },
  "traditional": {
    "preTaxContribution": 10000,
    "terminalGross": 76122.55,
    "terminalAfterTax": 59375.59
  },
  "difference": 1522.45,
  "recommended": "traditional",
  "interpretation": "Traditional wins when your retirement tax rate is below your current rate.",
  "note": "Estimate. Compares after-tax terminal value of an equal gross contribution; ignores contribution limits and RMDs."
}

Input schema

{
  "type": "object",
  "required": [
    "contribution",
    "years",
    "annualReturn",
    "currentTaxRate",
    "retirementTaxRate"
  ],
  "properties": {
    "contribution": {
      "type": "number",
      "description": "Gross contribution in USD",
      "examples": [
        10000
      ]
    },
    "years": {
      "type": "number",
      "examples": [
        30
      ]
    },
    "annualReturn": {
      "type": "number",
      "description": "Annual return as a decimal",
      "examples": [
        0.07
      ]
    },
    "currentTaxRate": {
      "type": "number",
      "description": "Current marginal rate as a decimal 0-1",
      "examples": [
        0.24
      ]
    },
    "retirementTaxRate": {
      "type": "number",
      "description": "Expected retirement rate as a decimal 0-1",
      "examples": [
        0.22
      ]
    }
  }
}

Output schema

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