Stock Average Calculator
Calculate your new average stock price after buying shares at different prices.
Your purchase average
Enter your figures and calculate to see the result.
This calculator is for informational purposes only and does not constitute investment advice. Brokerage, taxes and other charges are not included unless stated.
What is a Stock Average Calculator?
A stock average calculator combines purchases made at different prices into one weighted purchase cost basis average. Enter each quantity and price to see total shares, total investment and the average paid per share. All calculations happen in your browser.
How is the average stock price calculated?
Multiply the shares in each purchase by its price, add those investments, then divide by the total shares. Weighted Average Price = Total Amount Invested ÷ Total Shares. Calculations retain internal precision; monetary results are displayed to two decimal places.
Why a simple average is incorrect
A simple average gives every price equal weight, even when the purchases have different quantities. Buying 100 shares at 200 and 50 at 150 does not produce an average of 175. The larger purchase carries more weight, producing an average of about 183.33.
Example of stock averaging
100 shares × ₹200 = ₹20,000. Another 50 shares × ₹150 = ₹7,500. Total investment is ₹27,500 across 150 shares, so ₹27,500 ÷ 150 = ₹183.33 per share, rounded for display. The same formula works for more purchases and fractional shares. The arithmetic mean of ₹200 and ₹150 is ₹175, but it ignores the different quantities. The weighted average equals the arithmetic mean of these two prices only when the quantities are equal.
What does averaging down mean?
Averaging down means adding shares at a price below the existing purchase average, which lowers the combined average. For example, 100 shares at an average of ₹250 plus 100 at ₹180 results in 200 shares averaging ₹215. This arithmetic does not establish whether a purchase is suitable or profitable.
What happens when you buy above your average price?
A purchase above your current average increases the combined average. Buying at the same price leaves it unchanged. The Average Down mode supports all three cases and labels the direction of change.
How to calculate a target average price
Additional shares = Current Shares × (Current Average − Target Average) ÷ (Target Average − New Purchase Price). The target must lie strictly between the current average and the new price. For 100 shares averaging ₹250, buying at ₹180 to target ₹210 requires 133.333… mathematical shares. Rounding up to 134 gives an average of about ₹209.91, not exactly ₹210. If the current average already equals the target, no additional purchase is needed.
Stock average vs profit/loss
This tool calculates purchase cost basis averages only. It does not calculate unrealized profit/loss, fetch market prices or account for sales, stock splits, brokerage or taxes. Amounts are displayed in Indian rupees (INR); no currency conversion is performed. Enter all purchase prices in INR.
How to use
- Choose Multiple Purchases, Average Down Calculator or Target Average Calculator.
- Enter the required share quantities and prices in INR (₹). Use Add Another Purchase for additional buys, or remove unused rows.
- Select Calculate to see the result. In Target Average mode, compare the mathematical quantity with the whole-share estimate and its resulting average.
Frequently asked questions
How do I calculate my average stock price?
Add quantity multiplied by price for every purchase, then divide the total investment by the total number of shares. This is a weighted average rather than a simple mean of the prices.
How do I calculate average price after buying more shares?
Combine the cost of your existing shares with the new investment, then divide by the combined shares. You can enter the existing holding as one row using its quantity and current average.
What is averaging down?
It is buying additional shares below the current average purchase price, reducing the combined purchase average. A lower average does not guarantee a profit.
Can my average price increase after buying more?
Yes. Buying above your current average raises it. The calculator handles this and indicates that the average increases.
How many shares do I need to buy to lower my average?
Use Target Average mode with your current shares, current average, new purchase price and desired target. For a lower target, the new price must be below the target and the target below your current average. The whole-share estimate rounds up and may pass the target slightly.
Can I add more than two purchases?
Yes. Add Another Purchase has no fixed row limit. You can also remove rows, keeping at least one. Complete every remaining row before calculating; fractional quantities are supported.
Does this calculator include brokerage and taxes?
No. It uses purchase quantities and prices only. Brokerage, taxes and other transaction charges are excluded.
Can I use this for crypto or ETFs?
Mathematically, yes: the same weighted purchase-average formula applies to fractional units or shares. Transaction structures, fees and tax treatment can differ, and those differences are not modeled here.