Capital gains tax (long & short term) API

Estimate capital-gains tax: long-term gains via the US 2024 0/15/20 federal schedule stacked above ordinary taxable income, or short-term gains at the ordinary marginal rate, returning tax, after-tax gain, effective rate, and a per-rate-band breakdown. Estimate only; excludes 3.8% NIIT and state. Answers 'tax on a $50k long-term gain','short vs long-term capital gains tax','what rate on my stock sale','crypto capital gains tax'.

Price$0.01per request

MethodPOST

Route/v1/calc/tax-capital-gains

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

taxcapital-gainsltcgshort-terminvestingstockscryptocalc

API URLhttps://x402.hexl.dev/v1/calc/tax-capital-gains

Integration docs

Example request

{
  "gain": 50000,
  "ordinaryTaxableIncome": 50000,
  "filingStatus": "single",
  "term": "long"
}

Example response

{
  "year": 2024,
  "filingStatus": "single",
  "gain": 50000,
  "term": "long",
  "ordinaryTaxableIncome": 50000,
  "tax": 7500,
  "afterTaxGain": 42500,
  "effectiveRate": 0.15,
  "effectivePercent": 15,
  "rateBreakdown": [
    {
      "rate": 0.15,
      "amount": 50000,
      "tax": 7500
    }
  ],
  "note": "Estimate. US LTCG 0/15/20 schedule, stacked above ordinary taxable income; excludes 3.8% NIIT and state tax."
}

Input schema

{
  "type": "object",
  "required": [
    "gain"
  ],
  "properties": {
    "gain": {
      "type": "number",
      "description": "Capital gain in USD",
      "examples": [
        50000
      ]
    },
    "ordinaryTaxableIncome": {
      "type": "number",
      "description": "Ordinary taxable income the gain stacks on",
      "examples": [
        50000
      ]
    },
    "filingStatus": {
      "type": "string",
      "enum": [
        "single",
        "married",
        "head"
      ],
      "examples": [
        "single"
      ]
    },
    "term": {
      "type": "string",
      "enum": [
        "long",
        "short"
      ],
      "examples": [
        "long"
      ]
    },
    "holdingDays": {
      "type": "number",
      "description": "Days held; >365 = long-term"
    },
    "ordinaryMarginalRate": {
      "type": "number",
      "description": "Decimal marginal rate for short-term, e.g. 0.24"
    }
  }
}

Output schema

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