What is compound interest?

Compound interest means your returns are earned on both principal and previously accumulated returns, so growth can accelerate over time.

Can I estimate inflation-adjusted value?

Yes. Enter an inflation rate to see an approximate real-value estimate in today's purchasing power.

Is this a performance forecast?

No. This is deterministic math based on fixed assumptions. Real markets are variable and returns are not guaranteed.

How do I reach my target faster?

You can increase regular contributions, increase return assumptions cautiously, or extend the time horizon.

Compound Interest Calculator UPDATED | Growth Projection & Target Time

Overview

Understand how compounding changes outcomes

Compound interest growth is nonlinear. Over longer horizons, returns on prior returns can become a larger driver than new contributions.

Use this calculator to compare assumptions and set realistic contribution plans.

Complement with Drawdown Recovery for downside planning.

Growth projection

Estimate future value from principal, rate, and regular deposits.

Target planning

Estimate how long it could take to reach a portfolio goal.

Inflation context

View a rough inflation-adjusted value to compare nominal and real outcomes.

Calculator

Compound interest calculator

Auto-updates as you type. Switch between projection and time-to-target modes.

Initial amount ($)

Contribution per period ($)

Annual return (%)

Years

Inflation rate (%)

Contribution and compounding frequency

Monthly Weekly Yearly

Outputs

Future value

Total contributed

Growth from returns

Inflation-adjusted value

Portfolio multiple

Formula (periodic): nextBalance = currentBalance x (1 + r) + contribution.

Year-by-year projection

Year	Total contributed	Growth	Ending value

How it works

Compound growth mechanics

Core math

periodRate = annualRate / periodsPerYear

balance(next) = balance(current) x (1 + periodRate) + contribution

growth = endingValue - totalContributed

realValue = endingValue / (1 + inflation)^years

Practical notes

Use conservative return assumptions and test multiple scenarios (base, optimistic, defensive) instead of relying on a single estimate.

If volatility and drawdowns matter for your plan, pair this with Drawdown Recovery and Risk of Ruin.

Related tools

More risk and planning tools

Tools hub Drawdown Recovery Risk of Ruin Expectancy Risk Reward

FAQ

Compound interest FAQs

interest?

Compound interest means you earn returns on both principal and previously accumulated returns.

Does contribution frequency matter?

Yes. More frequent contributions can improve outcomes because more capital starts compounding sooner.

Can I include inflation?

Yes. Enter inflation to see a rough inflation-adjusted ending value.

Is this a forecast?

No. It is fixed-assumption math. Real returns and volatility vary over time.

How do I reach a target faster?

Increase contributions, adjust return assumptions carefully, or lengthen the investment horizon.

Disclaimer

Educational tool only. Results are scenario estimates based on fixed assumptions. Not financial advice.