Stock Split Calculator
Calculate how a stock split affects your shares and cost basis. Enter your position details and split ratio to see your adjusted share count and price per share.
You own 100 shares at $400 each (total value: $40,000). After a 4-for-1 split, you'll have 400 shares at $100 each — your total value remains $40,000, but each share is more affordable.
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Current holdings and split detailsResults
Before and after comparisonEnter your position details and split ratio to see how the split affects your holdings.
Before Split
After Split
Frequently Asked Questions
How splits affect your shares and cost basis
What is a stock split?
A stock split divides existing shares into multiple new shares, adjusting the price proportionally so the total market value stays the same. In a forward split (e.g., 4-for-1), each share becomes four shares at one-quarter the price. Companies split stock to make shares more affordable and increase liquidity.
A reverse split does the opposite — combining multiple shares into fewer shares at a higher price. Companies use reverse splits to meet exchange minimum price requirements or to appear more institutional-grade. In both cases, your total investment value remains unchanged immediately after the split.
How does a split affect my cost basis?
Your total cost basis does not change after a split — only the per-share cost basis adjusts. If you paid $200 per share and the stock splits 2-for-1, your cost basis becomes $100 per share. This is important for tax reporting because the IRS tracks gains and losses on a per-share basis.
Make sure to update your records after a split. Most brokerages adjust cost basis automatically, but if you track your own records, divide your original cost per share by the split multiplier for forward splits, or multiply it for reverse splits.
Does a stock split change my investment value?
No — a stock split does not change the total value of your investment. If you own $5,000 worth of stock before a split, you still own $5,000 worth after the split. You simply hold more shares at a proportionally lower price (forward split) or fewer shares at a higher price (reverse split).
However, stock splits can indirectly affect value over time. Forward splits often signal management confidence and can attract more retail investors, potentially increasing demand. Reverse splits may signal financial distress, though some companies use them purely for exchange compliance.
What is a reverse stock split and why do companies do it?
A reverse stock split combines multiple existing shares into fewer shares at a higher price. For example, in a 1-for-10 reverse split, every 10 shares become 1 share at 10 times the price. Your total investment value stays the same.
Companies typically execute reverse splits to meet minimum price requirements from stock exchanges (often $1 per share for NASDAQ/NYSE), to appear more attractive to institutional investors who avoid low-priced stocks, or to reduce the number of outstanding shares. Reverse splits are more common among struggling companies but are not always a negative signal.
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For informational and educational purposes only — not investment advice.