Investment Calculator – Portfolio Growth Over Time
Calculate investment portfolio growth with lump sum and monthly contributions over any time horizon.
📈 Finance📐 FV = P(1+r)^n + PMT×[(1+r)^n-1]/r
Initial investment ($)
Monthly contribution ($)
Annual return (%)
Investment years
Please enter valid values.
Formula & Reference
| Variable | Formula | Units |
|---|---|---|
| Investment Calculator – Portfolio Growth Over Time | FV = P(1+r)^n + PMT×[(1+r)^n-1]/r | $ |
Step-by-Step Examples
Example 1
$10K+$500/mo, 8%, 20yr
$10K initial, $500/month, 8%, 20 years.
- Contributed: $130,000 | Gains: $166,726
- Final: $296,726
✓ $296,726
Example 2
$0+$1K/mo, 7%, 30yr
Starting zero, $1K/month, 7%, 30 years.
- Final: $1,122,000 from $360K contributions
✓ $1,122,000
Example 3
$100K lump sum, 9%, 25yr
$100K, no monthly additions, 9%, 25 years.
- Grows to $862,308 — compounding works!
✓ $862,308
Real-World Applications
Investors
Project portfolio growth over time.
Young Adults
See power of starting early.
Retirement Planners
Model 401k and IRA growth.
Financial Advisors
Run client investment scenarios.
Common Mistakes to Avoid
⚠️
Expecting linear returns
Markets are volatile. 8% is a long-run average, not guaranteed.
⚠️
Ignoring taxes
Use tax-advantaged accounts (401k, IRA) to maximize compounding.
Frequently Asked Questions
Expected return? ▾
S&P 500 historical: ~10% nominal, ~7% real. Diversified 60/40: ~7% nominal.
Index funds vs stocks? ▾
Index funds match market, lower risk, lower fees. Most active managers underperform over 10+ years.
How much to invest? ▾
At minimum: capture full 401k employer match. Aim for 15-20% of income toward retirement.