Stock Average Price Calculator
Calculate your average buy price across multiple stock purchases and track unrealized P&L
Purchase Details
Purchase 1
Purchase 2
₹
Formulas
Avg Price = Total Investment / Total Shares
P&L = (Current Price − Avg Price) × Total Shares
Average Buy Price
—
Per share cost basis
Unrealized P&L
—
P&L %: —
Total Shares
Total Investment—
Current Value—
Return %—
Purchase Summary
| # | Shares | Buy Price | Investment | % of Total |
|---|
What is a Stock Average Price Calculator?
When a stock price falls after your initial purchase, "averaging down" by buying more shares reduces your average cost per share. This lowers your break-even price and increases potential gains when the stock recovers.
This calculator computes your new average buy price across multiple purchase tranches, helping you decide whether averaging makes strategic sense given your current portfolio.
lightbulb Example Calculation
Scenario: Ms. Divya Nair, 35-year-old investor from Kochi — bought 100 shares of Infosys at ₹1,500 in Jan 2023, then stock fell to ₹1,200. She wants to average down by buying 150 more shares at ₹1,200
1Total Investment = (50 × 200) + (100 × 160) = ₹10,000 + ₹16,000 = ₹26,000
2Total Shares = 50 + 100 = 150 shares
3Average Price = ₹26,000 ÷ 150 = ₹173.33 per share
✓ Result: New Avg Price = ₹173.33 | Break-even drops from ₹200 to ₹173.33
help_outlineHow to Use the Stock Average Calculator
- Enter the number of shares and the buy price (₹) for your first purchase in the Purchase 1 row.
- Click "Add Purchase" to add more rows for each subsequent purchase tranche — useful when you buy the same stock at multiple price points.
- Enter the current market price of the stock to compute your unrealized profit or loss at today's price.
- Click "Calculate Average" — results show your weighted average buy price, total shares, total investment, current portfolio value, and P&L.
- Review the Purchase Summary table to see each tranche's size as a percentage of your total investment.
Benefits
- Instantly find your break-even price after averaging down across multiple lots
- Shows unrealized P&L at any market price — no manual spreadsheet calculation needed
- Supports unlimited purchase tranches for systematic averaging strategies (SIP-style equity buying)
- Per-tranche breakdown reveals the weight of each purchase in your total cost
- Equally useful for averaging up (momentum) and averaging down (value buying) strategies
Key Terms
- Average Buy Price
- Total amount invested ÷ Total shares held; your true weighted cost per share across all purchases
- Averaging Down
- Buying additional shares when price falls below your original buy price, reducing average cost
- Averaging Up
- Adding shares as price rises; increases average cost but follows price momentum
- Unrealized P&L
- (Current Price − Avg Price) × Total Shares; paper gain/loss — only taxable when shares are sold
- Break-even Price
- The price at which total gain = total loss = ₹0; equals your average buy price
quizFrequently Asked Questions
What is averaging down and is it always a good strategy?
Averaging down means buying more shares when the price falls, reducing your average cost per share. Example: 100 shares at ₹500 + 100 more at ₹400 = average ₹450. It is beneficial if the stock recovers above ₹450. However, it is risky in "value traps" — companies whose fundamentals are deteriorating, not just temporarily undervalued. Averaging down works best in fundamentally strong companies during market-wide corrections, not in sector-specific declines.
How is average price different from a simple arithmetic average?
Simple average ignores how many shares were bought at each price. True average is quantity-weighted: Avg = Total Invested / Total Shares. Example: 10 shares at ₹100 + 90 shares at ₹50 → Simple avg = ₹75, but Weighted avg = (₹1,000 + ₹4,500) / 100 = ₹55. The weighted average (what this calculator computes) is the correct break-even price. Using the simple average would give a misleading, inflated cost basis.
How does averaging affect my capital gains tax when I sell?
In India, for listed equity, the tax department applies FIFO (First In, First Out) — the oldest shares are assumed sold first when you sell. So even though your average price is ₹450, the cost basis of the "first" shares sold is the original ₹500 for tax computation. LTCG (held >12 months) above ₹1.25 Lakh is taxed at 12.5%; STCG (<12 months) at 20%. Track individual purchase dates alongside this calculator for accurate tax planning.
Should I average up or average down in mutual funds?
For mutual funds, SIP (Systematic Investment Plan) inherently averages your cost automatically — buying more units when NAV is low and fewer when high (rupee-cost averaging). Deliberate averaging down in diversified mutual funds is uncommon because they rarely go to zero. Averaging up (lump sum additions during market highs) is less efficient than continuing regular SIPs. The best strategy is maintaining SIP discipline regardless of NAV level.
What is the break-even price and how do I use it for stop-loss placement?
Break-even price equals your average buy price — the price at which your investment returns exactly zero. If your average is ₹450, you need the stock at ₹450 just to recover your investment (before brokerage and STT). Traders often place stop-losses at 5–10% below break-even: ₹450 × 0.90 = ₹405 stop-loss. This calculator helps determine that threshold precisely so you can place orders mechanically rather than emotionally.