Savings Goal Calculator: Monthly Deposit and Time to Reach Your Goal

Plan your savings goal

Find the monthly deposit needed to reach a target balance, or estimate how long a monthly saving plan may take. The estimate assumes a constant APY, monthly compounding, and deposits at the end of each month.

Formatting only; enter all amounts in the same currency.

Enter 0 for no interest. The rate is an assumption, not a promise.

Your estimated plan

Monthly deposit needed
Estimated balance at target date
Total deposits including current savings
Estimated interest earned

How to use it

  1. Choose the monthly deposit required by a deadline or the time needed for a deposit plan.
  2. Enter your goal, current savings, APY, and the mode-specific value.
  3. Select a display currency and calculate. The currency selector does not exchange or convert amounts.

Formula

Let P be current savings, T the target, n monthly periods, and i the effective monthly rate. APY is converted as i = (1 + APY)1/12 − 1, with APY expressed as a decimal (4% = 0.04).

For end-of-month deposits C, projected balance is Bn = P(1+i)n + C × ((1+i)n − 1) / i. At 0% APY, the deposit term is C × n.

Required deposit when APY is positive: C = max(0, (T − P(1+i)n) × i / ((1+i)n − 1)). At 0%: C = max(0, (T − P) / n). Time mode returns the first whole month when the balance reaches the target.

Checked examples

Goal $10,000, current savings $1,000, 24 months, APY 4%: the monthly deposit rounded up to cents is $357.81. The modeled month-24 balance is $10,000.24, including $8,587.44 in deposits and about $412.80 interest.

With the same starting balance and APY but a $300 monthly deposit, the goal is reached in 29 months. The modeled balance is $10,210.16, including $9,700 in deposits and about $510.16 interest.

Limits and assumptions

  • This is a mathematical estimate, not financial advice or a guaranteed return. Rates can change; taxes, fees, minimum balances, and account rules are excluded.
  • APY is treated as an effective annual yield, converted to an equivalent monthly rate. Deposits occur at month-end.
  • One goal and one constant monthly deposit are modeled, for up to 1,200 months. Variable deposits, withdrawals, daily compounding, and inflation are not included.
  • If current savings already meet the goal, no additional deposit is needed. A plan that cannot reach the target within 100 years displays an error.
  • Enter amounts in one currency. Currency selection changes formatting only.

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