Investment & Planning

Stock Split & Reverse Split Calculator

Calculate your new share count and price after a stock split. Supports forward and reverse splits with preset ratios. Free tool for shareholders.

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What is Stock Split & Reverse Split Calculator?

A stock split changes the number of shares you own and the price per share, but the total value of your investment remains exactly the same. Our stock split calculator instantly shows you the before-and-after picture of any stock split — forward or reverse. Simply enter your current share count, the current price per share, and the split ratio. The calculator computes your new share count, adjusted price per share, and confirms that the total value is preserved. Mode tabs let you switch between forward splits (more shares, lower price) and reverse splits (fewer shares, higher price). Preset split ratios (2:1, 3:1, 3:2, 4:1, 1:2, 1:5) make it easy to model the most common corporate actions. Whether you're a shareholder preparing for an announced split or a student learning about corporate actions, this calculator makes the math instant and clear.

Steps:

  1. Select the split type: Forward Split or Reverse Split.
  2. Enter your current number of shares and price per share.
  3. Enter the split ratio or select a preset (2:1, 3:1, 3:2, 4:1, 1:2, 1:5).
  4. Review your new share count, adjusted price, and confirm total value is preserved.
  5. Use the scenario panel to test different split ratios.

Formula

Forward Split: New Shares = Old Shares × Split Ratio New Price = Old Price ÷ Split Ratio Reverse Split: New Shares = Old Shares ÷ Split Ratio New Price = Old Price × Split Ratio Total Value (Before) = Old Shares × Old Price Total Value (After) = New Shares × New Price Note: Total Value Before = Total Value After (split is value-neutral)

Use Cases

  • Shareholders preparing for announced stock splits
  • Investors calculating adjusted cost basis for tax reporting
  • Students learning about corporate actions and stock mechanics
  • Portfolio managers tracking position changes after splits

Key Benefits

  • Instantly see the impact of any stock split ratio
  • Verify that total value is preserved after the split
  • Model both forward and reverse splits with one tool
  • Use preset ratios for the most common corporate actions

Pro Tips

  • No action needed — your broker handles splits automatically
  • Update your cost basis records for accurate tax reporting
  • Use split-adjusted prices when analyzing historical performance
  • Stock splits often signal management confidence in future growth

Common Mistakes to Avoid

  • Thinking a stock split increases investment value
  • Forgetting to update cost basis per share after a split
  • Confusing stock splits with stock dividends or spin-offs
  • Not tracking split-adjusted historical prices for analysis

Key Terms Explained

Forward Split: Increases shares, decreases price proportionally
Reverse Split: Decreases shares, increases price proportionally
Split Ratio: The multiplier applied to share count (e.g., 2:1)
Cost Basis Adjustment: Per-share cost recalculated after split

Related Concepts

  • Stock Average Down Calculator – Adjust your cost basis
  • Stock Profit/Loss Calculator – Calculate returns after split
  • Dividend Calculator – Track dividend income

Example

You own 100 shares at $200 each (total value $20,000). The company announces a 2:1 forward split. New Shares = 100 × 2 = 200 shares. New Price = $200 ÷ 2 = $100 per share. New Value = 200 × $100 = $20,000 (unchanged). For a 1:2 reverse split: New Shares = 100 ÷ 2 = 50 shares. New Price = $200 × 2 = $400 per share. Value still $20,000.

Frequently Asked Questions

What is a stock split?
A stock split is a corporate action where a company divides its existing shares into multiple shares. In a forward split (e.g., 2:1), each share becomes 2 shares, and the price is halved. The total value of your investment remains the same — you just own more shares at a lower price per share. Companies split their stock to make shares more affordable and increase liquidity.
What is a reverse stock split?
A reverse stock split consolidates existing shares into fewer shares. In a 1:2 reverse split, every 2 shares become 1 share, and the price doubles. Companies use reverse splits to increase their share price, often to meet minimum listing requirements on exchanges or to appear more prestigious. Your total investment value remains unchanged.
Does a stock split change the value of my investment?
No. A stock split is purely cosmetic — it changes the number of shares and the price per share proportionally, but the total value of your holdings stays exactly the same. If you owned 100 shares at $200 ($20,000 total) and the company does a 2:1 split, you'll own 200 shares at $100 ($20,000 total).
Why do companies do stock splits?
Forward splits make shares more affordable for retail investors, increase trading liquidity, and signal management confidence in future growth. Apple, Tesla, and NVIDIA have all done splits to keep their share prices accessible. Reverse splits are typically done to avoid delisting from exchanges that require minimum share prices (often $1).
What are the most common stock split ratios?
The most common forward split ratios are 2:1, 3:1, 3:2, and 4:1. Common reverse split ratios include 1:2, 1:5, 1:10, and 1:20. A 2:1 split is the most common — it doubles your shares and halves the price. A 3:2 split gives you 3 shares for every 2 you owned.
Do I need to do anything when my stock splits?
No action is required on your part. Your broker automatically adjusts your share count and cost basis per share after the split effective date. The adjustment appears in your account overnight. However, you should update your records to reflect the new share count and per-share cost basis for tax purposes.
How does a stock split affect my cost basis?
Your total cost basis remains the same, but the per-share cost basis is adjusted. For a 2:1 split, your per-share cost basis is halved. If you originally paid $100/share for 100 shares ($10,000 total), after a 2:1 split you have 200 shares with a $50/share cost basis ($10,000 total). This matters for calculating capital gains when you sell.
Are stock splits taxable events?
No, stock splits are not taxable events in most jurisdictions. You don't owe taxes simply because your shares were split. Taxes are only triggered when you sell shares, and your adjusted cost basis (post-split) is used to calculate the gain or loss.
What is the difference between a stock split and a stock dividend?
A stock split changes the number of shares and price proportionally with no change in total value. A stock dividend issues additional shares to existing shareholders as a dividend (e.g., a 10% stock dividend gives you 1 extra share for every 10 owned). Both increase share count, but stock dividends are treated differently for accounting and sometimes tax purposes.
Can a stock split affect the stock price long-term?
While the split itself doesn't change value, studies show stocks often outperform in the months following a split. This is attributed to increased retail investor interest, improved liquidity, and the psychological effect of a lower share price. However, this is a correlation, not causation — the underlying business performance drives long-term returns.
What happens to fractional shares in a split?
Most brokers handle fractional shares automatically. In a 3:2 split, if you own 100 shares, you'd get 150 shares (no fraction). But in some unusual ratios, you might get fractional shares, which are typically either rounded up/down or paid out in cash by your broker.

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