Stock Split Calculator

Background.

Stock Split Calculator is a checking tool for people trying to restate share count and theoretical per-share price without changing total position value. A stock split changes units in the stated ratio; absent market movement, ownership percentage and aggregate value are unchanged. That definition leads directly to the displayed relationship: “new shares = old shares × split ratio; theoretical price = old price ÷ split ratio.”

The editable entries are shares before split, price before split, new shares per old share. Use values from the document or measurement that governs this stock split question; the defaults are only the worked fixture below. The main trap is specific to stock split: fractional-share handling, options, basis per share and actual post-announcement trading require broker records.

U.S. SEC Investor.gov, Stocks; shares, market value and corporate actions documents the convention or governing rule used here. The stock split output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is stock split calculator?

Stock Split is the relationship behind this decision: a stock split changes units in the stated ratio; absent market movement, ownership percentage and aggregate value are unchanged. On this page it means new shares = old shares × split ratio; theoretical price = old price ÷ split ratio. Fractional-share handling, options, basis per share and actual post-announcement trading require broker records; that is the line between the reported quantity and a broader investing analysis.

How to use this calculator.

1. 01Confirm that “new shares = old shares × split ratio; theoretical price = old price ÷ split ratio” matches the stock split convention you need.
2. 02Replace the fixture values for shares before split, price before split, new shares per old share with dated values from the governing record.
3. 03Keep all currencies, measurement units and time periods on the same basis before calculating.
4. 04Read shares after split together with this boundary: Fractional-share handling, options, basis per share and actual post-announcement trading require broker records.

The formula.

The calculation uses new shares = old shares × split ratio; theoretical price = old price ÷ split ratio. In this stock split model, the entered terms are shares before split, price before split, new shares per old share. A stock split changes units in the stated ratio; absent market movement, ownership percentage and aggregate value are unchanged, which is why the relationship is presented under this name rather than as a universal alternative. Fractional-share handling, options, basis per share and actual post-announcement trading require broker records. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Frequently asked questions.

References& sources.

1. [1]U.S. SEC Investor.gov, Stocks; shares, market value and corporate actions. Retrieved 2026-08-07. access: open unless marked otherwise.
2. [2]U.S. Securities and Exchange Commission. Investor.gov glossary: Stock splits. Retrieved 2026-08-07. independence: primary; access: open.
3. [3]U.S. Securities and Exchange Commission. Investor.gov glossary: Market capitalization. Retrieved 2026-08-07. independence: primary; access: open.