SIX CALCULATIONS, ONE STATEMENT
Simple interest calculator — see exactly what your principal earns
Model simple interest, compound growth, a loan's monthly repayment, a recurring savings plan, a credit card payoff or a multi-debt strategy — then read the result the way your bank or payroll department would print it, penny for penny.
Simple interest
Interest calculated on the original principal only — the way many short-term loans, bonds and late-payment penalties work.
Actual/360 is common on US commercial loans and slightly inflates the effective rate — this is often why a lender's figure differs from a quick manual estimate.
Full breakdown
Every period, principal-versus-interest split and running balance — the same shape as an amortization table from a bank.
Why the number should match your statement
Per-period rounding, not end rounding
Interest and principal are rounded to the cent on every single period, exactly as a bank's ledger does — not calculated in full precision and rounded once at the end, which is where most quick calculators drift from a real statement.
Real-world day-count rules
Simple interest supports both actual/365 and actual/360 conventions. Loans use standard reducing-balance monthly compounding. These are the same conventions written into most consumer credit agreements.
Every formula, shown in the open
No black box. The methodology panel below spells out exactly which formula ran, with your own numbers substituted in, so you can check it line by line against a payslip or bank letter.