Compound Investment Simulator

Explore how a fixed monthly contribution might have grown using historical month-end returns for large U.S. equities (dataset historical-equities). When the window runs past available history, the tool fills remaining months using each symbol’s stored five-year average annual return (Jan 2021 → Jan 2026, geometric). Not investment advice.

Inputs

Start year of window

Backtesting begins in January of this year.

Investment horizon

Stock / ETF

Monthly invested amount ($)

5-year average annual return (stored)

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Jan 2021 → Jan 2026, total return annualized.

When contributions begin (within the window)

First contribution: Jan 2010

Ending balance

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Total contributed

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Balance Over Time

Historical — actual monthly returns from the dataset

Contributions are added at the start of each month, then that month’s historical return is applied. Past performance does not guarantee future results.

Monthly ledger
Month	Contribution	Monthly return	Ending balance