Enter each purchase of a share, mutual fund, ETF or coin to get your average buying price, your break-even with charges and your profit or loss today, then see what buying more would do and how many shares a target average needs.
Your purchases
#
Price per share
Quantity
Remove
1
2
One line per buy: the price you paid per share and how many. Decimals work for fractional shares and crypto.
A calculator, not investment advice. Averaging down lowers your break-even but adds to a falling position; it only helps if the price recovers.
How to use the stock average calculator
Add a line for each buy: the price per share and the quantity. Add more lines with "+ Add purchase"; decimals work for fractional shares and crypto.
Optionally enter the total charges you paid and today's price, to see the break-even price and your profit or loss.
Under "If you buy more", try a quantity and price; under "Shares needed for a target average", enter the average you want.
Worked example
You bought 100 shares at ₹500 and 50 more at ₹430. You paid ₹71,500 for 150 shares, so your average is ₹476.67. At ₹450 the holding is worth ₹67,500, a loss of ₹4,000 (−5.59%). Buying 50 more at ₹400 brings the average to (₹71,500 + ₹20,000) ÷ 200 = ₹457.50. To get to an average of exactly ₹450 at ₹400 a share you'd need 150 × (476.67 − 450) ÷ (450 − 400) = 80 shares, costing ₹32,000.
Average after buying q more at p = (S × A + q × p) ÷ (S + q), where S is the shares you hold and A their average
Shares for a target average T = S × (A − T) ÷ (T − p), rounded up to whole shares
Works in any currency. A calculator, not investment advice: it doesn't know where the price will go next.
Frequently asked questions
How is the average price of a stock calculated?
Multiply each purchase price by the number of shares bought at that price, add those up, and divide by the total number of shares. 100 shares at ₹500 and 50 at ₹430 cost ₹50,000 + ₹21,500 = ₹71,500 for 150 shares, so the average is ₹476.67. Taking the plain mean of the two prices (₹465) is wrong because you bought more at ₹500.
How many shares should I buy to average down?
Shares to buy = shares you hold × (your average − target average) ÷ (target average − price you'll buy at). With 150 shares at ₹476.67, buying at ₹400 to reach a ₹450 average needs 150 × 26.67 ÷ 50 = 80 shares (₹32,000). The target has to be between the price you'll buy at and your current average: buying at ₹400 can never bring the average to ₹400 or lower.
Should I include brokerage and charges?
Yes, if you want the true break-even. Add the brokerage, STT or stamp duty, exchange fees and GST you paid on these buys in total; the calculator adds them to the cost and shows the break-even price per share. Your broker's app may show the average without charges, which is why the two can differ.
Does selling some shares change my average price?
Not under the average-cost method that brokers and portfolio apps use to show holdings: the shares you keep still have the same average. For tax, some countries use other rules (India uses first in, first out for capital gains), so the cost of the shares you sold can differ from the average.
Is averaging down a good idea?
It lowers your break-even price, but it also puts more money into a share that has fallen. It only helps if the price recovers. Many investors first check whether the fall is temporary or reflects a lasting problem with the business, and decide how much of their money they're willing to put into one stock. This calculator does the arithmetic; it isn't investment advice.
