Financial Calculator API
Common money math as an API. Calculate a loan: its monthly payment, total interest and total cost — with an optional full amortization schedule and the effect of extra monthly payments. Break down a mortgage into PITI (principal & interest, property tax, insurance, PMI and HOA) from a purchase price and down payment. Project compound interest and savings growth with optional recurring contributions (future value, total contributions, interest earned). And compute ROI on an investment, with annualised return when you supply the holding period. Every calculation is exact, deterministic and instant — pure local math, no third-party service and nothing stored. Live. 5 endpoints. Built for loan and mortgage calculators, savings and retirement planners, fintech tools and budgeting apps. Distinct from market-data and bank-data services. No upstream key.
api.oanor.com/fincalc-api
