复利计算器

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Compound Interest

What is "Compound Interest"?

Compound interest is when interest is calculated on both the initial principal and the accumulated interest from previous periods. This 'interest on interest' causes exponential growth over time. Albert Einstein reportedly called it the 'eighth wonder of the world' due to its powerful wealth-building effect.

Example: $10,000 at 7% compound interest for 30 years → $76,000 (7.6x the principal)

初始投资¥60,000.00

月度存款¥3,000.00

年利率（%）

0%10%20%

投资期限（年）

1y25y50y

Last Year Rate Assumption (%)

Used for the "this year vs last year" simulation.

复利频率Results update in real time when you move the rate/term sliders.

总投资额

¥780,000.00

总利息收入

+¥1,025,104.00

最终金额

¥1,805,104.00

增长图表

You vs Average

Benchmark: U.S. long-term average return assumed at 7%

Final gap: +¥0.00

This Year vs Last Year

Compares one-year outcomes using current and last-year return assumptions.

End-of-year difference: +¥808.00

💰

Compound Interest Result

¥1,805,104.00

✨ Estimated interest: ¥1,025,104.00

Expected value after 20 years (7% annual return)

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#CompoundInterest #Investment #Finance #WealthBuilding

什么是复利？

复利是对本金和以前期间积累的利息一起计算的利息。与仅对本金计算的单利不同，复利使您的资金随时间增长更快。

复利计算公式

A = P(1 + r/n)^nt

A = P(1 + r/n)^(nt)，其中A是最终金额，P是本金，r是年利率，n是每年复利次数，t是年数。

72法则

72法则是估算投资翻倍时间的简单方法。用72除以年回报率即可得到大约的年数。例如，在6%的年回报率下，您的投资将在约72÷6=12年内翻倍。

At 7% return, your investment doubles in about 10.3 years.

How to Read the Comparison Features

"You vs Average": See whether your assumptions outperform or underperform a U.S. long-term baseline.
"This Year vs Last Year": Quantify how a rate change shifts your one-year ending value under the same contribution plan.
Rate and term sliders update charts in real time so you can test scenarios quickly.

复利投资建议

✓尽早开始投资以最大化复利增长
✓定期投入，即使是小额也会积少成多
✓将收益再投资以加速增长
✓长期投资获得最佳结果

Last updated: 2025-01

📝 How to Use

Enter Initial Investment

Input your starting principal amount.

💡 Starting small is okay - consistency matters!

Set Annual Return Rate

Enter expected annual return rate (%).

💡 Stock funds average 7-10%, savings 2-4%.

Choose Investment Period

Enter how many years you plan to invest.

💡 Compound effect accelerates after 10 years!

Add Monthly Deposits (Optional)

If you plan to add money monthly, enter the amount.

💡 Regular contributions maximize compound growth.

🎯 Who is this for?

Useful for various situations

👶

College Fund for Kids

Start when your child is born to comfortably cover tuition costs.

Long-termEducation

🏠

Down Payment Savings

Calculate how long it takes to save for your dream home.

HomeSavings

🧓

Retirement Planning

Starting in your 30s makes comfortable retirement possible.

PensionRetirement

💎

Investment Simulation

Compare expected returns from ETFs, funds, and savings accounts.

ComparisonETF

💡

Expert Tip

The key to compound interest is 'time'. If you start investing $300/month at 30, someone starting at 40 can't catch up even with $1,000/month. The best time to invest was 10 years ago. The second best time is now.

— Warren Buffett's Investment Philosophy

❓ Frequently Asked Questions

How do I use the compound interest calculator?

Just enter your initial investment, annual return rate, and investment period. Optionally, you can add monthly contributions. The calculator shows your final amount, total interest, and yearly growth chart.

💡 Adding monthly deposits supercharges your compound growth!

What is the Rule of 72?

Divide 72 by your annual return rate to estimate how long it takes to double your money. For example, at 8% return: 72÷8=9 years to double your investment.

💡 Our calculator automatically shows you the Rule of 72 result!

What is the difference between simple and compound interest?

Simple interest applies only to principal, while compound interest applies to principal + accumulated interest. $10,000 at 5% for 20 years: simple interest = $20,000, compound = $26,500. The longer you invest, the bigger the difference.

💡 This is why compound interest is called "interest on interest"!

What is a realistic annual return rate?

It varies by investment: Savings 2-4%, Bonds 3-5%, Stock ETFs 7-10%, Individual stocks vary widely. For long-term planning, 7% is a conservative and realistic estimate.

💡 Remember: higher returns usually mean higher risk!

How early should I start investing?

The earlier, the better! Starting at 25 with $200/month at 7% gives you ~$550,000 by 65. Starting at 35 with the same amount yields only ~$250,000. A 10-year difference makes more than 2x difference!