Compound Interest Calculator
See how small regular contributions can grow into massive wealth over time.
How Compound Interest Builds Wealth
Compound interest means your returns earn returns. With regular monthly contributions, growth can accelerate over time.
Use this calculator to compare scenarios, adjust annual return assumptions, and estimate how long it takes to reach your target portfolio.
For higher planning quality, compare conservative, base, and optimistic return ranges instead of relying on one fixed number. This helps you estimate downside risk, contribution sufficiency, and whether your target date is realistically achievable.
Use this calculator as a planning baseline, not a guaranteed outcome. Return assumptions should be stress-tested against volatility and contribution consistency.
A practical approach is to define a minimum acceptable path first, then confirm whether your monthly contribution still reaches the target date under conservative returns.
Frequently Asked Questions
What is the difference between simple and compound interest?
Simple interest pays on principal only, while compound interest also pays on previously earned returns.
How often should I contribute?
Monthly contributions are common and effective. Consistency usually matters more than timing.
How should I choose an annual return rate?
Use conservative assumptions based on your asset mix and expected long-term market behavior.