$100 a month in the S&P 500 since 2023
Investing $100 every month in an S&P 500 index fund from January 2023 to Sep 2026 added up to $4,500. With dividends reinvested, it would be worth about $6,445.
Real monthly S&P 500 data, updated monthly. How we calculate$100 a month into the S&P 500 since Jan 2023 is worth
You would have put in $4,500 over 45 monthly buys.
If you had invested the whole $4,500 in Jan 2023, it would be worth $9,120. S&P 500 monthly average prices, dividends reinvested (recent months use the last reported dividend, Jun 2023). Data through Sep 2026. One buy per month at that month's average price; no fees or taxes. Past returns do not predict future returns.
The result
That is 45 monthly buys. The balance ended at 1.4× the money put in, a money-weighted return of 20.3% a year. Without reinvesting dividends it would be $6,299, so dividends added $147.
Prices rose along the way, so the deposits are worth more in today's money than their face value: $4,500 of deposits equals about $4,757 in today's dollars. Even measured that way, the plan ended 1.4× ahead.
The hardest stretch: the balance fell 5% from its high around Apr 2025, during the 2025 tariff sell-off. Someone who kept buying through that drop bought shares cheaply, which is a large part of the final number.
| After | Put in | Worth |
|---|---|---|
| Now (Sep 2026) | $4,500 | $6,445 |
How the balance grew, with dividends reinvested. No fees or taxes.
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Common questions
How much is $100 a month in the S&P 500 since 2023 worth today?
About $6,445 as of Sep 2026, from $4,500 invested, with dividends reinvested and no fees or taxes.
What was the yearly return?
20.3% a year, measured as a money-weighted return that accounts for when each monthly deposit went in.
What was the worst moment?
A 5% fall from the previous high around Apr 2025, during the 2025 tariff sell-off. The plan only reached today's value because the buying continued.
Will the next 4 years be the same?
Nobody knows. Past returns do not predict future returns, and the S&P 500 has had decade-long stretches with little gain.
Based on the S&P 500 monthly average level with dividends reinvested (an index fund before its small fee). Educational estimates, not investment advice. Past returns do not predict future returns.
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