About the Stock Split Calculator
A stock split changes the number of shares and their price without changing the total value of your holding. In a 3-for-1 split you get three shares for each one you own, and the price falls to a third. A reverse split does the opposite: 1-for-10 turns ten shares into one, at ten times the price. This calculator shows your new shares, the new price and any fraction of a share. Type your shares, the price and the split ratio and the stock split appears at once, with a few related figures underneath, and you can copy the result with one tap. The sums run in your browser, so nothing you enter is uploaded.
Updated October 2026
How to use the Stock Split Calculator
- 1Enter your shares, the price and the split ratio.
- 2Pick the units or options from the menus if the stock split tool offers them.
- 3Read the stock split in the large result box.
- 4Look at the extra rows for related figures.
- 5Press Copy result to keep the answer.
When you need the stock split
Companies split their shares to make them more affordable to small investors, and reverse split to lift a low share price, for example to stay listed on an exchange. Knowing the effect on your holding helps you to update your records, cost basis and charts.
Split-adjusted prices are used in historic price charts so that the line does not show a sudden fall. If you compare old prices with current ones, always adjust for splits.
How the stock split is worked out
New shares = old shares × new ÷ old. New price = old price × old ÷ new. The total value stays the same. If you own 100 shares at 300 each, a 3-for-1 split gives you 300 shares at 100, and your holding is still worth 30,000. In a 1-for-10 reverse split, 15 shares at 50 become 1.5 shares at 500: one whole share plus half a share that is usually paid out in cash.
Every answer on this page comes from that one rule, so you can check any result by hand with a calculator. The figures shown underneath, such as other units, are conversions of the same answer.
- Forward and reverse splits
- Fractional share shown
- Value before and after
Mistakes to avoid with stock split
A split by itself does not make a company more valuable, even though a lower price can feel cheaper. Fractional shares are handled differently by each broker. Check your broker's rules, and remember the split does not change your tax position on its own, but your cost per share does change.
On phone and computer
On a phone, type into the boxes one after another and read the stock split underneath; Copy result puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the stock split move. The stock split calculator works the same on both. After a split, work out your cost per share with Stock Average Calculator. Dividend Yield Calculator checks the new payout, ROI Calculator shows your return, and P/E Ratio Calculator compares the price with earnings.
Features
- Total value is unchanged
- Adjust charts for splits
- Check how your broker treats fractions
- Clear messages when the stock split inputs make no sense
- Copy the result with one tap
- Private: nothing is uploaded
Frequently asked questions
How do I calculate stock split?
New shares = old shares × new ÷ old. New price = old price × old ÷ new. The total value stays the same. If you own 100 shares at 300 each, a 3-for-1 split gives you 300 shares at 100, and your holding is still worth 30,000. In a 1-for-10 reverse split, 15 shares at 50 become 1.5 shares at 500: one whole share plus half a share that is usually paid out in cash.
What is the formula for stock split?
New shares = old shares × new ÷ old. New price = old price × old ÷ new. The total value stays the same. The stock split calculator applies it exactly and rounds only the displayed answer to six significant figures.
Does a split change my cost basis?
The total cost stays the same, but the cost per share falls in a forward split and rises in a reverse split.
Why do companies do reverse splits?
To raise a low share price, often to meet a minimum for listing, or to look more respectable to investors.
What happens to fractions of shares?
Most brokers pay cash for the fraction, but some hold fractional shares. Check with yours.
Is this stock split calculator free and private?
Yes. It is free, needs no account and runs in your browser, so the numbers you type are not uploaded or stored.