Average Price Calculator

A stock average price calculator computes the quantity-weighted average cost per share across multiple buy lots. It divides the total money invested (sum of price × quantity for each purchase) by the total shares bought. This gives you your blended cost basis — the price per share that your overall position must exceed to be in profit.

Use the weighted average formula: averagePrice = Σ(price × quantity) / Σ(quantity). For example, if you buy 10 shares at ₹50 and 20 shares at ₹40, the total investment is ₹500 + ₹800 = ₹1,300 and total shares are 30, so the average price is ₹1,300 / 30 = ₹43.33 per share. A plain average of the two prices (₹45) would be wrong because more shares were purchased at the cheaper price.

Averaging down means buying additional shares of a stock after its price has fallen below your original purchase price. Each new purchase at a lower price reduces your blended average cost per share, so your position returns to profit at a lower price than the original purchase. The risk is that you are increasing your exposure to an asset that is declining in value.

A simple average treats every purchase price equally regardless of how many shares were bought; a weighted average accounts for the number of shares in each lot. The two are equal only when every lot has the same quantity. In practice, lots differ in size, so weighted average is always the correct cost basis. Example: 10 shares at $50 and 20 shares at $40 → weighted average $43.33 vs simple average $45.00 — a difference of $1.67 per share.

Break-even price is the price per share at which selling your entire position returns exactly what you paid, with no profit or loss. Without brokerage or taxes, break-even equals your average purchase price. In reality, break-even is slightly higher because buy-side and sell-side transaction costs (brokerage, STT, GST, exchange charges) must also be recovered. This calculator shows the fee-free break-even.

Unrealized P&L = (Current Market Price − Average Price) × Total Shares. If the current price is above your average, the result is positive (unrealized gain). If it is below, the result is negative (unrealized loss). P&L % = (Current Price − Average Price) / Average Price × 100. These figures are pre-tax and assume you could sell all shares at the quoted current price.

Brokers like Zerodha and Groww apply the First In, First Out (FIFO) method when shares are sold: sales deduct from the oldest lots first. After a partial sale, the remaining average is recalculated on only the unsold shares, which can differ from a simple weighted mean of all historical buy lots. This calculator models buy-side averaging only — it assumes no shares have been sold. Use it to plan purchases, not to reconcile a broker statement after sales.

No. The average price and break-even price shown are fee-free and pre-tax. For an Indian equity position, actual break-even is higher because you must recover STT (0.1% on buy+sell for delivery), brokerage, GST on brokerage, exchange transaction charges, SEBI turnover fees, and the stamp duty on buying. On the sell side, short-term capital gains (STCG) at 20% or long-term gains (LTCG) at 12.5% (above ₹1.25 lakh) reduce net proceeds further.

This calculator supports up to 30 buy lots per calculation. You can start with the default two rows and add or remove rows as needed. If you have more than 30 distinct purchase events, combine the oldest lots manually: add their quantities and compute the weighted average of those combined lots before entering them.

Yes. The formula is identical for any asset where you make multiple purchases at different prices. For mutual funds, enter the NAV as the price and the number of units as the quantity. For ETFs and bonds the same weighted-average logic applies. The calculator is currency-agnostic and works for USD, INR, EUR, GBP, and JPY positions.

Cost basis is the total amount you paid for a holding, and average cost basis per share is that total divided by shares owned. It matters because capital gains tax is calculated on the difference between the sale price and the cost basis. An accurate cost basis ensures you do not overpay tax on a sale. Most tax authorities and brokers use either specific lot identification or average cost methods to determine this.

Averaging down reduces your cost basis and lowers the price at which you break even, which is mathematically appealing. However, it concentrates more capital in a stock that is already underperforming and raises your total risk exposure. Whether it is a sound strategy depends on why the stock fell — a temporary market dip versus fundamental deterioration. This calculator shows the arithmetic effect; it does not provide investment advice. Consult a SEBI-registered investment adviser for personal guidance.