A one-time lump sum can grow dramatically with time. Try multiple return assumptions to see a realistic range.
Calculate $10,000 growth| Scenario | Value in 15 years | Starting amount |
|---|---|---|
| Left in cash (0% growth) | $10,000 | $10,000 |
| Purchasing power (3% inflation) | ~$6,400 in today's dollars | $10,000 |
| Invested at 7% | ~$27,600 | $10,000 |
| Invested at 10% | ~$41,800 | $10,000 |
In 15 years, $10,000 left sitting in cash will still be $10,000 — but thanks to inflation at around 3% per year, its purchasing power will have dropped to around $6,400 in today's dollars. That's a silent loss of $3,600 just from doing nothing. Invested at 7% however, that same $10,000 grows to around $27,600 — turning inflation from an enemy into a problem you've left well behind. This comparison is one of the strongest arguments for investing rather than holding cash long term.
For a lump sum, the two biggest factors are time and your average return. Regular contributions can amplify the result even more.
Even $100/month can change the outcome a lot. Contributions compound too.
Yes. You’ll usually see compounding become more noticeable in the second half of the timeline.
The difference is usually small compared to your return rate and time. Pick one and be consistent when comparing.
Inflation reduces purchasing power. This calculator shows nominal growth; consider inflation separately if you want “today’s dollars”.
Sometimes. Lump sum invests earlier; dollar-cost averaging reduces timing risk. This page is for modelling only.
Yes. The maths is the same — treat $ as your currency unit.