Kultranz API: Free US Personal Finance Data & Calculators

The Kultranz API turns the data engine behind this site into clean JSON endpoints. Every number traces back to a real government source - no estimates, no scraping, no guesswork. It’s the same data that powers the calculators you’ve been using here, exposed for developers.

What you get

Endpoint	Returns	Example
`GET /paycheck`	Take-home pay (fed + FICA + state)	`?salary=120000&state=CA&filingStatus=single`
`GET /cost-of-living`	Equivalent salary between two metros	`?fromCity=Austin, TX&toCity=San Francisco, CA&salary=100000`
`GET /tax-brackets`	Federal + state brackets as JSON	`?state=NY&filingStatus=mfj`
`GET /col-index`	50-metro RPP table	`?city=Albuquerque, NM`
`GET /compound-interest`	Future value + yearly series	`?principal=10000&monthly=500&rate=7&years=20`
`GET /net-worth`	Assets, liabilities, net worth	`?cash=10000&investments=50000`
`GET /debt-payoff`	Avalanche / snowball schedule	`?debts=[{...}]&extra=200&mode=avalanche`
`GET /budget`	50/30/20 split	`?income=5000`
`GET /salaries`	Real BLS wage percentiles by job x city	`?job=nurse&city=Chicago`

Base URL

https://api.kultranz.com

All requests must go through RapidAPI, which injects the X-RapidAPI-Host and X-RapidAPI-Key headers on every call. Grab a free key on RapidAPI to start testing - the free tier gives 100 requests/day, no credit card.

Examples

Substitute YOUR_RAPIDAPI_KEY with your own key from RapidAPI.

Take-home pay

curl "https://kultranz.p.rapidapi.com/paycheck?salary=120000&state=CA&filingStatus=single" \
  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \
  -H "X-RapidAPI-Host: kultranz.p.rapidapi.com"

Cost of living

curl "https://kultranz.p.rapidapi.com/cost-of-living?fromCity=Austin,%20TX&toCity=San%20Francisco,%20CA&salary=100000" \
  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \
  -H "X-RapidAPI-Host: kultranz.p.rapidapi.com"

Salary data

curl "https://kultranz.p.rapidapi.com/salaries?job=nurse&city=Chicago" \
  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \
  -H "X-RapidAPI-Host: kultranz.p.rapidapi.com"

Response format

Every response uses a uniform envelope:

{
  "data": { },
  "meta": {
    "source": "BLS OEWS + BEA RPP + U.S. Census ACS + IRS (via kultranz.com)",
    "vintage": "2026",
    "year": 2026
  }
}

Errors return { "error": { "code": "...", "message": "..." } } with the appropriate HTTP status.

Pricing

Tier	Price	Quota
Basic	Free	100 requests/day
Pro	$10/mo	10,000 req/mo, then ~$0.002/req
Ultra	$49/mo	150,000 req/mo
Mega	$199/mo	1,000,000 req/mo

Billing, API keys, and rate-limiting are managed by RapidAPI - we never see your payment details.

Data sources & vintage

Wages: BLS Occupational Employment and Wage Statistics (OEWS) - 20 occupations x 50 metros, with 10th/25th/median/75th/90th percentiles.
Cost of living: BEA Regional Price Parities (RPP), US average = 100.
Housing & income: U.S. Census American Community Survey (ACS) 5-year estimates.
Tax brackets: IRS 2026 - federal standard deduction, brackets, FICA Social Security wage base ($184,500), Medicare + additional Medicare.

Full details on our methodology page.

Try it

The same calculators on this site call these endpoints under the hood. Run the paycheck calculator, the cost-of-living tool, or browse salaries by job to see the data in action - then grab a RapidAPI key when you’re ready to build with it.