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Stock split calculator

A split changes how many shares you own and the price per share, but not the total value. In a 2-for-1 split you get 2 shares for every 1 at half the price; in a 1-for-10 reverse split you get 1 share for every 10 at ten times the price. Fractional shares left over are often paid out in cash.

Shares you own before the split

Share price before the split ($)

Your total cost basis ($, optional)

Split ratio: new shares

for every old shares

Fractional shares

Shares after split–

Price per share after–

Fractional share–

Cash in lieu–

Total value (unchanged)–

Cost basis per share after–

Example shown: a 1-for-10 reverse split. For a 2-for-1 forward split enter 2 and 1.

How stock splits are calculated

For an A-for-B split, new shares = old shares × A ÷ B and new price = old price × B ÷ A. Your total value and total cost basis stay the same; cost basis per share is total basis ÷ new shares. If the result has a fraction and your broker pays cash in lieu, you receive fraction × new price in cash, and that small sale can be taxable.

Common questions

Does a stock split change the value of my investment?

No. On the split date your total value is the same; you just hold more (or fewer) shares at a lower (or higher) price.

Is a stock split taxable?

The split itself is not taxable. Cash paid for fractional shares is treated as a sale of that fraction and can create a small gain or loss.

Why do companies do reverse splits?

Often to raise a low share price, for example to keep meeting an exchange's minimum price rule.

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Last reviewed October 31, 2026. This calculator gives estimates for education and planning only. Results depend entirely on the numbers you enter and the assumptions stated on this page; they are not investment, tax or trading advice, and real results will differ.