Stock split calculator
This adjusts share count, price, and per-share cost basis for a forward or reverse split. The position's market value and total cost stay the same. A split does not, by itself, change what the holding is worth. The stock split guide uses the same example.
New shares = old shares × (shares received ÷ shares exchanged). New price = old price × (shares exchanged ÷ shares received).
Shares after the split
Enter the position and the split ratio.
How to adjust a position for a split
- Enter shares, price, and cost per share. Cost per share is the basis you track for the lot, before the split.
- Enter the split as shares received and shares exchanged. A 4-for-1 split is 4 received and 1 exchanged. A 1-for-10 reverse split is 1 received and 10 exchanged.
- Check that the totals match. Share count and per-share figures change. Market value and total cost basis do not.
Frequently asked questions
- How does a stock split change shares and price?
- Multiply the share count by the shares you receive and divide by the shares you exchange. Divide the price and the per-share cost basis by that same factor. A 4-for-1 split turns 100 shares at $200 into 400 shares at $50. A $150 cost basis becomes $37.50 a share. The position is still worth $20,000, and the total cost is still $15,000.
- What do you enter for a reverse split?
- Enter fewer shares received than shares exchanged. A 1-for-10 reverse split is 1 received and 10 exchanged. The share count falls and the price rises. A leftover fraction is disclosed as theoretical cash-in-lieu at the post-split price. Brokers may round or pay cash on different terms. Market value after the split is not guaranteed.
- Is this investment advice?
- No. The calculator is for general informational and educational purposes only. A split does not, by itself, change what the position is worth.
Related tools
- Market cap calculatorConfirm that price times the new share count is the same cap.
- Implied share price calculatorDivide a target cap by the post-split share count.
- Stock average calculatorRestate lots after the split before averaging.
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