How it works
Contributions are monthly and nonnegative. A nominal annual rate and compounding frequency produce an equivalent monthly rate, including fractional compounding periods: (1 + annual rate / frequency)^(frequency / 12) − 1. This smooth accrual convention may differ from an account that credits only on specific dates. Daily means 365 periods, including leap years. Returns remain constant in each scenario and are hypothetical, not guaranteed. Taxes, fees, inflation and withdrawals are excluded. Internal precision is retained; displayed money rounds to two decimals.
The formulaEnd-of-month recurrence: B_next = B × (1 + r_month) + contribution. Beginning-of-month recurrence: B_next = (B + contribution) × (1 + r_month).
Good to know
Are these personalized financial recommendations?
No. These are arithmetic planning tools with editable hypothetical assumptions. Actual account terms, taxes, fees, cash flows and lender statements can differ.
Where do my numbers go?
Calculation inputs stay in this page. The finance tools do not place them in links, make calculation requests or save them automatically. CSV and print exports are created only when you choose them. Existing site delivery and performance services still operate; see Privacy.
Which currency and rounding do you use?
Choose a display currency and enter every amount in that same currency. No exchange conversion is performed. These tools use two-decimal money displays. Loan and debt schedules round monthly interest and balances to cents; savings models keep internal precision. Values are bounded to keep calculations reliable.