Investment Calculator: How to Plan Your Portfolio
Published August 2026 | 8 min read
Whether you're saving for retirement, a house, or financial independence, you need a plan. Our free investment calculator shows how your money grows with different contributions, returns, and timeframes.
How to Use the Calculator
Enter your details:
- Initial investment — What you're starting with
- Monthly contribution — What you add each month
- Expected return — Annual growth rate (7-10% for stocks historically)
- Time horizon — How many years until you need the money
The Impact of Fees
Fees destroy returns. Here's what a 1% fee costs on a $500/month investment at 8% over 30 years:
- No fee: $745,000
- 0.5% fee: $697,000 (-$48,000)
- 1.0% fee: $652,000 (-$93,000)
- 1.5% fee: $610,000 (-$135,000)
Use low-cost index funds (expense ratios under 0.20%) instead of expensive actively managed funds.
Asset Allocation by Age
| Age | Stocks | Bonds |
|---|---|---|
| 20s-30s | 90% | 10% |
| 40s | 80% | 20% |
| 50s | 70% | 30% |
| 60s+ | 60% | 40% |
Dollar-Cost Averaging vs. Lump Sum
Research shows lump sum investing wins 66% of the time because markets trend up. But dollar-cost averaging (investing monthly) reduces the risk of bad timing and is better for most people psychologically.
💡 Start Investing Today
Compare brokers with zero commissions and low fees.
Compare Investment Accounts →The Bottom Line
Use our investment calculator to map your path. The most important factors: start early, contribute consistently, keep fees low, and stay invested through market downturns.
Related: Compound Interest Calculator | Retirement Calculator
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