Compound Interest & SIP Calculator 2026 - Visualize the Snowball Effect

Q: Do regular investments always profit?

Regular investing averages costs; 5+ years markedly raise the odds of profit, with no short-term guarantee.

Q: Is 8% annualized realistic?

CSI 300 total return has averaged 9–11% p.a.; active funds 10–15%. Single years can swing ±20–50%.

The Compound Interest & SIP Calculator visualizes the snowball effect, computing compound future values and regular-investment returns in one click. At 8% p.a. for 30 years, 1 yuan becomes 10.06; at 10%, it becomes 17.45 — the keys are time and steady contributions. Supports custom principal, annual rate, compounding frequency and investment amount. Great for beginners and long-term investors. Computed locally; for planning reference only, not investment advice.

Investment Parameters

Initial Principal (CNY)

Per-Period Investment (CNY)

Investment Frequency

Investment Horizon (years)

Expected Annual Return (%)

Compound Growth Report

Final Total Assets

Initial Principal -

Total Invested -

Total Principal -

Snowball Gains (Profit) -

Asset Growth Curve

About the Compound Interest & SIP Calculator

What is compound interest?

Compound interest is called "the eighth wonder of the world." Its core is interest on interest: not only does principal earn, past interest itself earns in each new period. Stretch the timeline and the growth curve turns exponential.

What does regular investing do?

Few people can invest a lump sum, so a fixed monthly amount is the most practical approach. In bull or bear markets alike, regular investing averages your cost basis and builds wealth through discipline.

Return Reference

Money funds and large CDs run about 2%–3%; conservative wealth products and bond funds 4%–6%; long-term regular investment in broad indices (CSI 300, S&P 500) has historically averaged 8%–10%. Anything promising 15%+ usually carries severe risk of principal loss. For planning only — not investment advice.

Frequently Asked Questions

How powerful is compounding?

At 8% p.a. over 30 years, 1 yuan becomes 10.06; at 10%, 17.45. Compounding is all about time and steady contributions.

Do regular investments always profit?

Regular investing averages out costs; over 5+ years the odds of profit improve markedly, though short-term losses are still possible.

Is 8% annualized realistic?

The CSI 300 total-return index has averaged ~9–11% p.a. long-term; active funds 10–15%. Single years can swing −20% or +50% — be ready.

Compound vs simple interest — how big is the gap?

CNY 100K at 10% for 30 years: simple interest ends at 400K, compound at 1.745M — more than 4x apart.

📚 Further Reading

Want to dig into the math behind Compound & Regular Investing? Recommended reading:

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Compounding & regular investing: the scientific snowball

Compounding is the eighth wonder of the world. Four real scenarios show CNY 1,000/month over 30 years snowballing from CNY 360K contributed into CNY 1.5M.

⏱ About 6 min read