Bonus Share Calculator

Bonus Share Calculator: How to Calculate Bonus Shares Easily?

When a company announces a Bonus Share, you get extra shares in your Demat account for free. However, many investors get confused about how many total shares they will have after the bonus, what their New Buy Price will be, and how much the Share Price will drop on the bonus adjustment date.

With this free Bonus Share Calculator, you can check all these numbers in seconds. Simply enter your share quantity and select the bonus ratio—the calculator updates everything automatically without needing to press a submit button.

What is a Bonus Share? (Explained Simply)

When a company makes good profits, it often happily gives away additional shares to its existing shareholders for free. These free shares are called Bonus Shares. You don’t have to pay a single penny for this.

Who receives how many bonus shares depends on the bonus ratio the company announces.

A small example: Suppose a company announces a 1:1 bonus. This means that if you have 1 old share, the company will give you 1 new share for free.

If you already have 100 shares, the calculation would be like this:

• Your old shares: 100
• Bonus Ratio: 1:1
• Get free bonus shares: +100
• Total shares after bonus: 200

One important thing to remember: Your number of shares will double (from 100 to 200) when you receive a bonus, but your total value will not double immediately. Because, as the number of shares increases, the market price of the shares also adjusts in the same proportion. It’s like cutting a large pizza into 8 pieces instead of 4—the number of pieces increases, but the total amount of pizza remains the same!

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What Does This Bonus Share Calculator Show You?

This calculator gives you a complete picture of your holding before and after the bonus issue:

• Free Bonus Shares: Exact number of whole bonus shares you will get.
• Total Shares: Your old shares plus the new bonus shares.
• New Buy Price: Your updated average buy price per share and the exact percentage drop.
• New Share Price: Estimated market price of 1 share after the bonus adjustment.
• Old vs. Bonus Share Split Bar: A visual bar showing what percentage of your total holding comes from old shares versus bonus shares.
• Before Bonus vs. After Bonus Table: A side-by-side comparison of your Total Shares, Buy Price, Market Price, Money Invested, Current Value, and Total Profit / Loss.
• Fractional Share Alert: An automatic notice if your share quantity and ratio create a fractional (decimal) share entitlement.

How to Use This Bonus Share Calculator? (Step-by-Step Guide)

Follow these simple steps to check your bonus share calculation:

Step 1: Enter Your Shares (Quantity) — Required

Enter the number of shares you currently have in your Demat account.

• Type any whole number directly into the box (for example, 100).
• Use the − and + buttons to adjust your quantity quickly, or tap one of the quick buttons (10 Shares, 50 Shares, 100 Shares, 500 Shares, 1,000 Shares).

Step 2: Enter Your Buy Price (₹) — Optional

Enter the buying price of 1 share from your portfolio (for example, ₹500).

• Note: This field is optional. If you only want to check how many free bonus shares you will get, you can leave it blank. Entering it shows your New Buy Price and Money Invested.

Step 3: Enter Current Share Price (₹) — Optional

Enter the current market price of 1 share on NSE or BSE before the bonus adjustment (for example, ₹1,000).

• Note: The calculator does not fetch live stock prices automatically. Entering the current price shows your New Share Price, Current Value, and Total Profit / Loss.

Step 4: Select Bonus Ratio (New : Old) — Required

Choose the bonus ratio announced by the company:

• Tap any of the 6 preset ratio buttons: 1:1, 1:2, 2:1, 1:5, 3:1, or 4:1.
• If your company announced a different ratio, type the numbers into the New Shares and Old Shares boxes manually.
• Right below the ratio boxes, check the blue Meaning box—it explains the ratio in plain English (for example: “Meaning: You get 1 free bonus share for every 1 old share you hold”) so you never mix up the numbers.

Step 5: Check Your After Bonus Result

Your results update instantly in the 2. After Bonus Result panel:

1. Top 4 Result Cards: View your Free Bonus Shares, Total Shares, New Buy Price (with % Lower badge), and New Share Price.
2. Share Split Bar: See the percentage split between your Old Shares and Bonus Shares.
3. Before Bonus vs. After Bonus Table: Compare every number side-by-side, including your Money Invested, Current Value, and net Total Profit / Loss.
4. Summary Box: Read a clear one-line summary of your result in the green banner.

Step 6: Share or Copy Your Result

Tap 📲 Share Result to send your calculation directly on WhatsApp, or tap 📋 Copy Result to copy the summary text. To clear all boxes and start fresh, click the ↺ Reset button at the top right.

How to Understand a Bonus Share Ratio (New : Old)?

In a bonus announcement, the ratio is written as New Bonus Shares : Old Shares Held:

• The first number (New Shares) tells you how many free bonus shares you receive.
• The second number (Old Shares) tells you how many existing shares you must hold to get those bonus shares.

Easy Tip to Remember: In a 1:2 bonus, you get fewer bonus shares than what you already hold (half). In a 2:1 bonus, you get more bonus shares than what you already hold (double).

Which Formulas Does This Bonus Share Calculator Use?

Here are the exact formulas used behind the scenes, explained with simple examples:

1. Free Bonus Shares (Whole Shares)

Since Demat accounts only credit whole shares (not decimals like 0.5 shares), the calculator rounds down to the nearest whole number:

• Formula: Free Bonus Shares = Floor((Your Shares × New Shares) ÷ Old Shares)
• Example: If you hold 100 shares and the bonus ratio is 1:2: (100 × 1) ÷ 2 = 50 free bonus shares.
• What if there is a Fractional Share? Suppose you hold 3 shares and the ratio is 1:2. The math gives 3 × 1 ÷ 2 = 1.5 shares. The calculator shows 1 whole bonus share and displays an info note explaining that fractional share settlement (for the remaining 0.5 share) depends on company rules and is excluded from Current Value and Profit/Loss.

2. Total Shares After Bonus

• Formula: Total Shares = Your Shares + Free Bonus Shares
• Example: 100 old shares + 100 bonus shares (in a 1:1 bonus) = 200 total shares.

3. Money Invested

Because bonus shares are free, your total invested amount remains the same before and after the bonus:

• Formula: Money Invested = Your Shares × Your Buy Price
• Example: 100 shares × ₹500 buy price = ₹50,000.

4. New Buy Price After Bonus

After receiving bonus shares, your original investment is spread across a higher number of shares:

• Formula: New Buy Price = Money Invested ÷ Total Shares After Bonus
• Example: ₹50,000 invested ÷ 200 total shares = ₹250.00 per share (a 50.0% drop in average cost per share).

5. New Share Price (Estimated Ex-Bonus Price)

• Formula: New Share Price = Current Share Price × Old Shares ÷ (Old Shares + New Shares)
• Example: If the current share price is ₹1,000 and the ratio is 1:1: ₹1,000 × 1 ÷ (1 + 1) = ₹500.00.

6. Current Value (Before & After Bonus)

• Before Bonus: Your Shares × Current Share Price (100 × ₹1,000 = ₹1,00,000)
• After Bonus: Total Shares × New Share Price (200 × ₹500 = ₹1,00,000) (Note: If your calculation has a fractional share, the After Bonus value shows the value of whole shares only.)

7. Total Profit / Loss

When both Buy Price and Current Share Price are entered, the calculator shows your overall profit or loss:

• Formula: Total Profit / Loss = Current Value (After Bonus) − Money Invested
• Example: ₹1,00,000 − ₹50,000 = +₹50,000 (+100.00%).

Why Does Your Buy Price Go Down After a Bonus?

New investors often worry when they see their buy price drop from ₹500 to ₹250 after a 1:1 bonus. Does this mean your investment value went down?

No. Your total invested money stays the exact same.

• Before Bonus: 100 shares × ₹500 = ₹50,000 invested.
• After 1:1 Bonus: 200 shares × ₹250 = ₹50,000 invested.

Because the same ₹50,000 is now divided across 200 shares instead of 100, the average buy price per share becomes ₹250.

Important Things to Keep in Mind

1. Manual Price Entry: This calculator does not fetch live NSE/BSE prices automatically. Enter the current share price manually for accurate results.
2. Estimated New Share Price: The New Share Price is a theoretical calculation based on the bonus ratio. On the actual Ex-Bonus date, the real market price may move slightly higher or lower depending on market demand and supply.
3. Fractional Shares: If your ratio creates a fractional share, companies usually sell the combined fractional shares through a trustee and credit the cash to your bank account. This cash payout is not included in the calculator.
4. Portfolio Average Cost vs. Income Tax Cost: The New Buy Price shown in the calculator is your portfolio’s adjusted average cost. Under Indian Income Tax rules (FIFO method), the cost of original shares remains your purchase price while the acquisition cost of bonus shares is generally treated as ₹0 when calculating capital gains tax. Always consult a qualified tax professional before filing taxes.

Please Note: Bonus shares are issued to existing shareholders in a specified ratio. To understand bonus issues, stock splits, and other corporate actions, investors can also refer to the educational material published by SEBI.