This stock split calculator shows what a stock split or a bonus issue does to your holding. Enter your shares, your average cost and the ratio. The tool returns your new share count, new cost per share and the adjusted price, and it confirms that the value of your holding does not change.
Quick answer: A split or bonus raises your share count and lowers the price and your cost per share by the same factor. Your total cost and total value stay the same. Enter your numbers below.
Split and bonus adjuster
Check the ratio in the company’s notice on NSE or BSE before you enter it. Some websites label ratios differently, so the official filing settles any doubt.
How to Use the Stock Split Calculator: Reading Ratios
| Notice says | Meaning | Enter in the tool |
|---|---|---|
| Bonus 1:1 | 1 new share for every 1 held | Bonus, A = 1, B = 1 |
| Bonus 1:2 | 1 new share for every 2 held | Bonus, A = 1, B = 2 |
| Bonus 2:1 | 2 new shares for every 1 held | Bonus, A = 2, B = 1 |
| Split Rs 10 to Rs 1 | Each share becomes 10 shares | Split, old = 10, new = 1 |
| Split Rs 10 to Rs 5 | Each share becomes 2 shares | Split, old = 10, new = 5 |
Many investors confuse 2:1 with 1:2. However, the first number is usually the new shares you receive, and the second is the shares you hold. Therefore, a 1:2 bonus adds only half a share per share, while a 2:1 bonus triples your count.
Worked Example: Bonus Issue With Made-Up Numbers
| Item | Before 1:1 bonus | After 1:1 bonus |
|---|---|---|
| Shares held | 100 | 200 |
| Average cost per share | Rs 1,000 | Rs 500 |
| Total cost | Rs 1,00,000 | Rs 1,00,000 |
| Price per share | Rs 2,400 | Rs 1,200 |
| Value of holding | Rs 2,40,000 | Rs 2,40,000 |
Worked Example: Stock Split With Made-Up Numbers
| Item | Before 1:10 split | After 1:10 split |
|---|---|---|
| Face value | Rs 10 | Rs 1 |
| Shares held | 10 | 100 |
| Price per share | Rs 24,000 | Rs 2,400 |
| Value of holding | Rs 2,40,000 | Rs 2,40,000 |
Bonus Issue Versus Stock Split
| Feature | Bonus issue | Stock split |
|---|---|---|
| Face value | Unchanged | Falls |
| Company reserves | Fall (capitalised) | Unchanged |
| Share count | Rises | Rises |
| Price per share | Falls | Falls |
| Value of your holding | Unchanged | Unchanged |
| Tax on receipt | None | None |
What Else Changes After a Bonus or Split
- EPS and book value per share fall by the same factor, while the PE and P/B ratios stay unchanged. Use the PE ratio calculator to check.
- Dividend per share is adjusted for comparison, but your total dividend stays the same if the payout per old share holds. See the dividend yield calculator.
- Historical charts are adjusted by data vendors, so older prices look lower than they were.
- Holding period for bonus shares generally starts on the allotment date. Confirm current tax rules with a qualified adviser.
When to Use the Stock Split Calculator
Use the stock split calculator in three situations. First, run it right after a corporate action to update your share count and cost per share. Second, run it before the record date to see what the new numbers will look like. Third, use it when you compare old and new price charts, since the stock split calculator shows the adjusted price that vendors use. Consequently, you avoid mistaking a rebased price for a crash.
Why Companies Split Shares or Issue Bonus Shares
Companies use these actions to improve liquidity and make a high share price more accessible to small investors. A bonus also puts accumulated reserves into share capital. However, neither action creates value. Earnings growth and business quality still drive returns, which is why our shareholders’ equity guide and dividend payout ratio guide matter more than the share count.
Common Mistakes
- Entering 2:1 when the notice says 1:2.
- Buying after the ex-date and expecting the bonus or split.
- Treating the lower price as a bargain.
- Comparing old EPS with new EPS without adjusting.
- Forgetting to update your cost per share in your own records.
Frequently Asked Questions
How do I calculate shares after a bonus issue?
Multiply your shares by A and divide by B to get the bonus shares, then add them to your holding. The tool does this and rounds fractions down.
How do I calculate shares after a stock split?
Divide the old face value by the new face value and multiply your shares by the result. A split from Rs 10 to Rs 1 gives 10 times as many shares.
Does my total investment change after a bonus or split?
No. Your total cost and total value stay the same. Only the number of shares and the per-share figures change.
What is my new cost per share?
Divide your total cost by your new share count. The tool shows it when you enter your average cost.
Is a bonus share taxable when I receive it?
No tax applies on receipt. Bonus shares generally carry a nil cost of acquisition, and tax rules can change, so check with an adviser.
What is the difference between a split and a bonus?
A split cuts the face value, while a bonus converts reserves into new shares at the same face value. Both raise the share count.
Does the calculator save my numbers?
No. It runs in your browser and sends nothing to our server.
Final Thoughts
Use the adjuster after every bonus or split to keep your records correct. Then read the company’s notice for the dates. Explore the rights issue calculator and the stock market glossary on Investor Weekly News. This page is educational and is not investment advice.