# Finance Calculators

Exact loan, savings, growth, break-even and cash-flow calculations for agents, with no model guesswork.

## How to pay

Machine-payable over x402. USDC on: Base (eip155:8453), Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp), Polygon (eip155:137), Arbitrum One (eip155:42161).
No accounts. No API keys. No signup. The paying wallet is the account.

## Machine-readable

- OpenAPI: https://finance-calculators.x402tookit.com/openapi.json
- x402 manifest: https://finance-calculators.x402tookit.com/.well-known/x402
- Catalog (free): https://finance-calculators.x402tookit.com/catalog
- Health (free): https://finance-calculators.x402tookit.com/health
- Uptime (free): https://finance-calculators.x402tookit.com/uptime

## Endpoints (9)

### GET /break-even — $0.02
Break-even units and revenue from fixed costs, unit price and unit variable cost, plus profit at a target volume.
Params: fixed_costs: number, price: number, variable_cost: number, target_units?: number
Example: https://finance-calculators.x402tookit.com/break-even?fixed_costs=5000&price=25&variable_cost=9&target_units=500

### GET /compound-interest — $0.02
Future value of savings with compounding and monthly contributions: balance, contributions, interest earned, by year.
Params: principal: number, annual_rate_pct: number, years: number, monthly_contribution?: number, compounds_per_year?: integer
Example: https://finance-calculators.x402tookit.com/compound-interest?principal=10000&annual_rate_pct=5&years=10&monthly_contribution=0&compounds_per_year=12

### GET /loan-payment — $0.02
Loan payment, total interest and amortization preview from principal, annual rate and term, monthly or other frequency.
Params: principal: number, annual_rate_pct: number, years: number, payments_per_year?: integer
Example: https://finance-calculators.x402tookit.com/loan-payment?principal=200000&annual_rate_pct=6&years=30&payments_per_year=12

### GET /mortgage-affordability — $0.02
Home price you can afford under the 28/36 rule from income, monthly debts, down payment, rate and term.
Params: annual_income: number, monthly_debts?: number, down_payment?: number, annual_rate_pct: number, years?: integer, tax_insurance_monthly?: number
Example: https://finance-calculators.x402tookit.com/mortgage-affordability?annual_income=120000&monthly_debts=500&down_payment=60000&annual_rate_pct=6.5&years=30&tax_insurance_monthly=600

### GET /npv-irr — $0.02
Net present value and internal rate of return (IRR) for a list of cash flows, with a clear accept/reject-at-rate verdict.
Params: flows: string, discount_rate_pct?: number
Example: https://finance-calculators.x402tookit.com/npv-irr?flows=-1000%2C500%2C500%2C500&discount_rate_pct=10

### GET /pay-convert — $0.02
Convert pay between hourly, weekly, biweekly, monthly and annual for a given hours per week and weeks worked.
Params: amount: number, per: string, hours_per_week?: number, weeks_per_year?: number
Example: https://finance-calculators.x402tookit.com/pay-convert?amount=32&per=hour&hours_per_week=40&weeks_per_year=52

### GET /roi-cagr — $0.02
Return on investment and compound annual growth rate (CAGR) from a start value, end value and years held.
Params: start: number, end: number, years: number
Example: https://finance-calculators.x402tookit.com/roi-cagr?start=100&end=200&years=10

### GET /rule-of-72 — $0.02
Years to double money at a growth rate (exact and by the rule of 72), and how long inflation takes to halve buying power.
Params: rate_pct: number
Example: https://finance-calculators.x402tookit.com/rule-of-72?rate_pct=8

### GET /savings-goal — $0.02
Monthly saving needed to reach a goal by a date, given what you already have and an expected annual return.
Params: goal: number, years: number, current?: number, annual_return_pct?: number
Example: https://finance-calculators.x402tookit.com/savings-goal?goal=50000&years=5&current=5000&annual_return_pct=4

## Terms

Results are arithmetic on the numbers you supply, computed locally and provided as is. They are illustrations, not financial, tax or investment advice, and ignore fees, taxes and inflation unless stated. Verify with a qualified professional before relying on them.