Choosing the right investment vehicle is crucial for maximizing the power of compound interest. The best compound interest investments combine strong average returns, low fees, automatic reinvestment, and a long time horizon — all of which amplify the compounding effect dramatically.
In this guide, we rank the top compound interest investments for 2025, explain the returns each offers, and show how they perform over time using our compound interest calculator.
What Makes an Investment Great for Compounding?
Not all investments compound equally. The best vehicles for compound growth share these characteristics:
- Consistent returns: Higher and more reliable average annual returns = faster compounding
- Low fees: Management fees reduce your effective rate. A 1% fee can cost tens of thousands over 30 years
- Automatic reinvestment: Dividends and interest should compound back into the investment
- Long-term stability: Compound interest needs time — volatile investments that force early withdrawals lose compounding potential
1. S&P 500 Index Funds — Best Overall
Average Annual Return: ~10% (7% inflation-adjusted)
S&P 500 index funds are widely considered the gold standard for long-term compound investing. They track the 500 largest US companies, automatically reinvest dividends, and typically charge fees under 0.05% annually. Popular options include Vanguard VOO, Fidelity FXAIX, and iShares IVV.
Over 30 years, $10,000 in an S&P 500 index fund at 10% grows to roughly $174,494. With $300/month contributions, that becomes over $700,000.
Low cost, high historical returns, automatic dividend reinvestment, tax efficiency in retirement accounts, and extreme diversification make index funds the best compound interest vehicle for most investors.
2. High-Yield Savings Accounts — Best for Safety
Current APY: 4.5–5.5%
High-yield savings accounts (HYSAs) at online banks currently offer 4.5–5.5% APY, significantly more than traditional bank savings accounts (0.5% or less). They're FDIC-insured up to $250,000, making them risk-free for capital preservation while still benefiting from compound interest.
Best for: emergency funds, short-term savings goals (1–5 years), and as a "safe" portion of your portfolio.
3. Dividend Reinvestment Plans (DRIPs)
Average Total Return: 8–12%
DRIPs automatically reinvest dividends from individual stocks or funds to purchase more shares. This creates a powerful compounding loop — each new share generates more dividends, which buy more shares. Over decades, dividend reinvestment can account for 40–50% of total investment returns.
4. Real Estate Investment Trusts (REITs)
Average Annual Return: 9–12%
REITs are companies that own income-producing real estate and are required to distribute 90% of taxable income as dividends. Reinvesting these dividends creates strong compound growth while providing real estate exposure without owning property. REITs are available through most brokerage accounts.
Comparison: $10,000 at Different Investment Rates (30 Years)
| Investment Type | Avg Rate | $10K → 30 Yrs | Risk Level |
|---|---|---|---|
| S&P 500 Index Fund | 10% | $174,494 | Medium |
| REIT | 9% | $132,677 | Medium |
| Total Stock Market ETF | 9.5% | $153,088 | Medium |
| Corporate Bonds | 5.5% | $49,840 | Low-Med |
| High-Yield Savings | 5% | $43,219 | Very Low |
| Treasury Bonds | 4.5% | $37,453 | Very Low |
Use our compound interest calculator to model any of these investment types with your specific contribution amounts and time horizon.
Model Your Investment Portfolio
Use our free calculator to see exactly how each investment type would grow your money over time.
Calculate Your GrowthFrequently Asked Questions
S&P 500 index funds, total market ETFs, dividend reinvestment plans, REITs, and high-yield savings accounts. Index funds offer the best balance of return, cost, and simplicity for most investors.
High-yield savings: 4-5%. Bonds: 3-6%. Real estate: 8-12%. S&P 500: ~10% historically. For conservative retirement planning, use 6-7% (inflation-adjusted).
Yes, always. Dividend reinvestment compounds your returns by automatically buying more shares, which generate more dividends — a self-reinforcing wealth cycle that dramatically improves long-term returns.
They're the best for most investors. Low fees (0.03-0.10%), automatic dividend reinvestment, historical returns of ~10%, and zero individual stock selection required.