Estimate the future value of an investment from a lump sum plus regular contributions.
Compounding 5,000 plus 200/month for 15 years at 7% annually grows to an estimated 77,637.19.
Investment growth combines an initial deposit, ongoing contributions, and a rate of return, compounded over time. Small differences in return rate or in how early you start have an outsized effect on the final balance because of compounding.
P is the initial investment, PMT is the periodic contribution, r is the periodic rate of return, and n is the number of periods. Investing $10,000 upfront plus $300/month at a 7% annual return for 25 years grows to roughly $286,000 — the majority of which is investment growth, not contributions.
| Years | Total contributed | Projected balance |
|---|---|---|
| 10 | $46,000 | $72,000 |
| 20 | $82,000 | $196,700 |
| 30 | $118,000 | $447,200 |
Contributions vs. total balance — $10,000 initial + $300/month at 7%
Example 1 — No initial deposit, contributions only: Starting from $0 and contributing $250/month at a 7% annual return for 20 years grows to about $130,000 — entirely from consistent contributions and compounding.
Example 2 — Higher return assumption: The same $10,000 + $300/month scenario at a 9% return (instead of 7%) over 30 years grows to roughly $620,000 — about 39% more than at 7%, showing the outsized effect of a few extra percentage points of return over decades.
Example 3 — Delaying by 10 years: Investing $300/month at 7% for 30 years reaches roughly $340,000. Waiting 10 years to start (investing for only 20 years) reaches about $147,000 — less than half — illustrating why starting early outweighs the cost of a delayed, larger later contribution in most cases.
| Assumed net return | Projected balance |
|---|---|
| 7% (no fees) | ~$447,000 |
| 6% (1% annual fee) | ~$358,000 |
| 5% (2% annual fee) | ~$288,000 |
What rate of return should I assume? Long-run historical averages for diversified stock portfolios are often cited around 7–10% before inflation, though future returns are never guaranteed.
Does this account for taxes? This is a pre-tax growth projection; taxable accounts, tax-deferred accounts, and tax-free accounts each have different real-world outcomes.
Is a lump sum or regular contributions better? Historically, investing a lump sum immediately tends to outperform spreading it out, but regular contributions reduce timing risk and suit most savers' cash flow.
How much does a 1% fee difference really matter? Over a 30-year horizon, even a 1 percentage point fee difference can reduce the final balance by roughly 15–20%, since fees compound against your returns every single year.
Should I adjust my projected return for inflation? For a realistic sense of future purchasing power, many planners subtract expected inflation (historically often 2–3%) from the nominal return to get a "real" growth rate.
Does this calculator model market volatility? No — it assumes a smooth, constant annual return for simplicity; real markets fluctuate year to year, so actual results will vary even if the long-term average matches the assumption.
How does contribution frequency (monthly vs. annually) affect the outcome? More frequent contributions (e.g., monthly instead of annually) slightly increase the final balance, since money is invested and starts compounding sooner on average throughout the year.
Investing $5,000 upfront plus $200/month at an assumed 8% annual return for 20 years grows to roughly $128,000 — compare this to the same monthly contribution with no starting lump sum, which would grow to about $115,000, showing how even a modest head start compounds meaningfully over two decades.
Future value: What a sum of money today, plus growth, will be worth at a future date.
Compounding frequency: How often investment returns are calculated and reinvested — annually, monthly, daily, etc.
Lump sum: A single, one-time investment amount, as opposed to regular ongoing contributions.
What's the difference between this and the Compound Interest Calculator?
This tool adds regular ongoing contributions on top of a starting lump sum, while the Compound Interest Calculator focuses on how a single lump sum grows on its own.