Skip to content

Stock split calculator

By Jude Wallis

A stock split multiplies share count by the split factor and divides price by it. A 2 for 1 split turns 100 shares at $80 into 200 shares at $40. Market value stays $8,000 in this identity.

Market capitalisation after the split

$8,000.00

200 shares at $40.00. Same capitalisation as $8,000.00 before.

New share count
200
Adjusted price
$40.00
Capitalisation after
$8,000.00

Share count immediately before the split.

$

Quoted price immediately before the split.

N in an N-for-one split. 2 is two-for-one.

Put this on a class page: one iframe, free, for Google Sites, Canvas, WordPress or Notion.

On this page

The formula

new shares=old shares×N,new price=old priceN\text{new shares}=\text{old shares}\times N,\quad \text{new price}=\frac{\text{old price}}{N}

NN is the number of new shares for each old share. Share count rises by NN while price divides by NN.

Count and price move inversely

A 2 for 1 split multiplies 100 shares by 2 and divides the $80 price by 2. The result is 200 shares at $40. How stock splits work explains the event.

Market value is unchanged by the identity

Before the split, 100×80=8000100\times80=8000, or $8,000. After it, 200×40=8000200\times40=8000, also $8,000.

A 4 for 1 example

A factor of 4 turns 100 shares into 400 and an $80 price into $20. Both sides still equal $8,000 of market capitalisation.

Scope of the identity

This calculation isolates the mechanical split. Market trading after the event is a separate source of price changes. This is educational material, not financial advice.

Worked examples

A 2 for 1 stock split

An investor has 100 shares at $80. A split issues 2 new shares for each old share. What are the new count, price and market value?

  1. New shares are 100×2=200100\times2=200.
  2. New price is 80/2=4080/2=40, so $40.
  3. Value before is 100×80=8000100\times80=8000, or $8,000. Value after is 200×40=8000200\times40=8000, also $8,000.

The split produces 200 shares at $40. Market value is $8,000 before and $8,000 after from 100 shares at $80.

A 4 for 1 stock split

An investor has 100 shares at $80. A split issues 4 new shares for each old share. What are the new count, price and market value?

  1. New shares are 100×4=400100\times4=400.
  2. New price is 80/4=2080/4=20, so $20.
  3. Value before is $8,000. Value after is 400×20=8000400\times20=8000, also $8,000.

The split produces 400 shares at $20. Market value is $8,000 before and $8,000 after from 100 shares at $80.

Multiplying both count and price

The count multiplies by the split factor, but price divides by it. Multiplying both would create value from the split identity alone.

Common questions

Does a split create market value?

No. In the mechanical identity, total value is unchanged.

What does 4 for 1 mean?

Each old share becomes 4 new shares, and the reference price divides by 4.

Is this financial advice?

No. It is educational material for split arithmetic.

Keep reading

This page is educational material, not financial advice. The figures come from the formula shown and assume the inputs you enter hold for the whole term. Your own rate, fees, taxes and timing will differ, so treat the output as arithmetic to check a decision against, not as a recommendation.