Plan a savings goal
Enter a target, the amount already saved and an assumed APY. Find deposit amount estimates the regular transfer needed within your chosen timeframe. Find time to reach goal uses your planned transfer to estimate a finish date. Monthly dates retain today’s day where possible and use the last day of a shorter month.
The equivalent periodic rate is r = (1 + APY / 100)^(1 / frequency) − 1. After n end-of-period deposits, the balance is Start × (1 + r)^n + Deposit × ((1 + r)^n − 1) / r. At zero interest, deposits simply add to the starting balance. Weekly and biweekly counts are rounded down to whole deposits within the modeled timeframe.
Frequently asked questions
How is APY converted to a periodic rate?
The model uses (1 + APY / 100) raised to 1 / deposits per year, minus 1. APY already includes compounding; dividing APY by 12 would overstate a monthly yield.
When are deposits made?
Deposits are added at the end of each month, two-week period or week, starting one period from today. A required deposit is rounded up to the next cent.
Are these returns guaranteed?
No. APY is an input assumption, not a current offer. Rates stay fixed in this model; tax, fees and inflation are excluded.