Free how long to save calculator
Calculate how many months it takes to reach a savings goal — enter goal, current balance, monthly contribution, and APY, updated live, as you type.
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Hypothetical projection at fixed rate. Actual savings returns vary. Excludes taxes.
Results are estimates. Consult a professional.
How the how-long-to-save calculator works
This calculator solves for time: given a savings goal, a starting balance, a regular monthly contribution, and an interest rate, how many months until you reach your target? It rearranges the standard future-value formula to isolate the number of periods (n) and solves using logarithms.
The key is recognizing that total growth comes from two streams — the compound growth of your existing balance and the accumulated growth of each monthly contribution. Both streams grow at the same rate, so they can be combined into a single logarithmic expression to solve for n.
Worked example: $20k goal, $3k saved, $400/mo
You want to save $20,000 for a car purchase. You already have $3,000 and can save $400 per month in an account earning 4% APY. How long will it take?
Months to reach common goals from $0 at 4% APY
The table below shows how many months it takes to reach four savings goals from a $0 starting balance at four monthly contribution levels, all at 4% APY. Starting with even a small existing balance will reduce these times noticeably.
| Goal | $250/mo | $500/mo | $1,000/mo | $2,000/mo |
|---|---|---|---|---|
| $10,000 | 39 mo | 20 mo | 10 mo | 5 mo |
| $20,000 | 78 mo | 38 mo | 19 mo | 10 mo |
| $50,000 | 188 mo | 90 mo | 44 mo | 22 mo |
| $100,000 | 348 mo | 164 mo | 78 mo | 38 mo |
Source: calculated using Federal Reserve compound interest methodology; assumes monthly compounding at 4% APY from $0 starting balance.
Tips for reaching your goal faster
Two levers control time-to-goal: the monthly contribution amount and the interest rate. Even small adjustments to either can shave months off your timeline.
- Increase contributions at the margin — adding $50/mo to a $400/mo plan may not feel significant, but it cuts weeks off a 3-year timeline. Run this calculator to see the exact impact before dismissing 'small' increases.
- Use the highest APY you can find — the difference between 2% and 5% APY on a $15,000 average balance is $450 per year, which is like adding $37.50/mo in free contributions.
- Apply windfalls as lump-sum deposits — a $1,000 bonus applied today reduces the remaining gap and makes every future month's contribution more powerful.
- Review your goal amount — sometimes the target has flexibility. If reducing your goal by 10% cuts 3 months off your timeline, that trade-off may be worth it.
- Avoid early withdrawals — raiding a dedicated savings account resets the clock painfully. A separate account with a meaningful label (e.g., 'Car 2026') reduces the temptation to dip in.
Accuracy and limitations
This calculator assumes a constant APY and equal monthly contributions throughout the savings period. Real-world savings rates are variable and contributions may fluctuate with income changes. The result is the number of complete months needed — in practice you will reach your goal partway through the final month, so the actual elapsed time may be slightly less than the calculated figure.
This calculator is provided for educational and planning purposes only. It does not constitute financial advice. Consult a licensed financial advisor for personalized guidance.
Time-to-goal savings terms defined
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