Stock Average Calculator
Add every purchase you have made in a stock and get one weighted average price — your real break-even. Then find out what it would take to move that average where you want it.
How the average is worked out
A weighted average, then the arithmetic that answers “how many more shares?”
The formulas
- Cost of one purchase
- Buy price × Quantity
- Total invested
- Sum of every purchase cost
- Shares held
- Sum of every quantity
- Average buy price
- Total invested ÷ Shares held
- Market value
- Current price × Shares held
- Unrealised profit or loss
- Market value − Total invested
- Shares to reach a target average
- (Total invested − Target × Shares held) ÷ (Target − Buy price)
The last line is the first rearranged. Setting the new average equal to your target and solving for the quantity is all the “average down” planner does.
The example above, step by step
- 1200 shares at 150.00 cost ₹30,000.00, and 300 at 120.00 cost ₹36,000.00.
- 2That is ₹66,000.00 for 500 shares, an average of 132.00 — not the 135.00 midpoint, because the larger purchase pulls the figure towards its own price.
- 3At 126.00 the holding is worth ₹63,000.00, which is ₹3,000.00 below what you paid (-4.5%).
- 4Bringing the average down to 126.00 by buying at 110.00 takes 188 more shares, or ₹20,680.00. That lands the average at 125.99 across 688 shares — a fraction under the target, because shares are bought whole.
What averaging down actually does
It moves your break-even price. Whether that helps is a separate question.
Buying more of a falling stock lowers the price at which the position gets back to flat. It does not recover the loss, and it does not make the original decision any better — it puts more money behind it. The useful test is whether you would open this position today, at today’s price, knowing nothing about what you already own.
Notice how much work the quantity does. Averaging down with a small top-up barely moves the figure, because the average is weighted: to pull it a long way you have to buy an amount comparable to what you already hold. That is the number this calculator makes explicit, and it is often larger than people expect before they run it.
There is also a hard limit. You cannot average down to a price below what the market is charging, however many shares you buy — the tool says so rather than returning a figure that cannot be acted on. Deciding your full position size and your exit before the first purchase is what keeps averaging from becoming a way to postpone a loss.
Reading the result
- Average buy price
- Your break-even price before charges. Every purchase counts in proportion to its size, not its position in the list.
- Unrealised profit or loss
- What the holding is worth today against what it cost. Nothing is realised until you sell, and the percentage is measured on the money you put in.
- Shares to buy
- How many more shares at your chosen price bring the average to your target, rounded up to a whole share.
- New average
- Where the average actually lands once that whole-share rounding is applied — usually a fraction the right side of the target.
Charges, and what your broker shows
This page averages trade prices. A contract note may not.
The average here is built from the prices you actually paid. Some brokers fold brokerage, securities transaction tax and stamp duty into the cost of acquisition, which nudges the average they display slightly above this one. Neither is wrong — they answer different questions, and it is worth knowing which your broker is showing before you compare.
For capital gains the cost of acquisition is the figure that counts, so use your contract note rather than this average when you file. To see what charges do to a single trade end to end, the risk to reward calculator prices them into the profit and the loss.
Other calculators
Same approach, different question.
Frequently Asked Questions
How to average stock price using a calculator?
To average stock price using a calculator, enter the purchase price and share quantity for each buy order. The calculator computes the weighted average price by dividing total money spent by total shares owned. For example, buying 100 shares at ₹150 and 200 shares at ₹120 totals ₹39,000 for 300 shares, resulting in an average stock price of ₹130 per share.
How to average stock price calculator works?
A stock average price calculator works by applying a weighted average formula: Total Money Invested ÷ Total Shares Held. Unlike a simple midpoint average, it weighs each transaction by the volume of shares purchased. This allows investors to plan "average down" strategies by calculating how many new shares at current market prices are needed to bring the overall cost basis down to a target price.
Why is my average not the midpoint of my buy prices?
Your average price differs from the simple midpoint because the purchases were made with different share quantities. The weighted average shifts towards the price where you bought a larger quantity of shares. Buying larger volumes at lower prices pulls your overall average price down much faster.
How many shares do I need to reach a target average?
To reach a target average price, the calculator solves for the additional quantity needed at a given buy price using the formula: Shares Needed = (Total Invested − (Target Average × Total Shares)) ÷ (Target Average − New Buy Price). Note that you cannot average down to a target price below the current market buying price.
Is averaging down a good idea?
Averaging down lowers your break-even price on a stock position, but it also increases your total monetary risk in that single stock. It works best when fundamental analysis confirms the company remains strong and the price dip is temporary. Pre-determining your total maximum allocation prevents over-exposing your portfolio.
Does the average price include brokerage and taxes?
This calculator averages the trade execution prices. Some brokers fold brokerage and transaction taxes into your cost of acquisition on contract notes. For tax purposes, refer to your broker contract note or tax P&L statement.