What is a stock average calculator?
A stock average calculator finds your weighted average buy price when you purchase the same stock at different prices. Instead of averaging prices directly, it weights each purchase by the number of shares bought.
Add each purchase with quantity and buy price. The tool shows average cost per share, total shares, and total amount invested—useful for tracking break-even after multiple buys.
How can a stock average calculator help you?
Investors who accumulate shares over time—through SIP in stocks, dips, or bonus lots—often hold multiple buy prices. Knowing the weighted average tells you the true cost basis for P&L and tax planning.
- Calculate average buy price after two or more purchases at different rates.
- See total shares and capital deployed before deciding to add or trim a position.
- Compare your average cost with current market price alongside the brokerage calculator for net trade costs.
How does this stock average calculator work?
The calculator uses the standard weighted average formula. Each purchase contributes Quantity × Price to the numerator; the denominator is the sum of all quantities.
Average Price = Σ(Quantity × Price) / Σ(Quantity)
Where –
| Quantity | Number of shares bought in each purchase |
|---|---|
| Price | Buy price per share for that purchase |
Total investment = Σ(Quantity × Price); total shares = Σ(Quantity)
Worked example
You buy 100 shares at ₹250 and later 200 shares at ₹275. Total investment = (100 × 250) + (200 × 275) = ₹80,000. Total shares = 300. Average price = 80,000 / 300 = ₹266.67 per share.
If you add a third purchase of 50 shares at ₹300, total investment becomes ₹95,000 on 350 shares, and the new average is about ₹271.43.
How to use this stock average calculator
Enter quantity and buy price for each purchase. Use Add purchase for additional lots (up to 10). Results update as you edit values.
To estimate round-trip trading charges on a sell, use the brokerage calculator. For overall return on invested capital, try the ROI calculator.
What this calculator does not include
Brokerage, STT, GST, corporate actions (splits, bonuses), sold shares, or FIFO/LIFO tax lots are not modeled. The average shown is a simple weighted mean of entered buy prices for planning—not tax or portfolio accounting advice.
Frequently asked questions
How is weighted average price different from a simple average?
A simple average of ₹250 and ₹275 is ₹262.50, treating both buys equally. Weighted average is ₹266.67 because the larger 200-share purchase at ₹275 pulls the average up. Always weight by shares bought.
Can I use this after selling some shares?
This tool calculates average buy price for the purchases you enter. If you have sold part of your holding, your broker’s remaining cost basis may differ depending on accounting method. Enter only lots that are still held for a rough check.
Does average price include brokerage?
No. Enter the trade price per share before charges. Use the brokerage calculator to estimate fees separately if you want all-in cost.