How it works
Uses monthly contributions and the same equivalent-monthly growth convention as the compound interest calculator. Contributions are nonnegative; returns are constant hypothetical nominal rates. Required contributions round up to cents. Time is the first end-of-month balance at or above the target, up to 1,200 months. An already-met target takes zero months in time mode; a future target still accounts for possible negative returns. No taxes, fees, inflation or withdrawals. A target may be unreachable with the entered assumptions.
The formulaRequired contribution = max(0, [target − future value of current savings] ÷ future value of 1 contributed monthly). Time mode repeats the monthly balance recurrence until the target is reached.
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.