You bought a stock, the price dropped, and you bought more. What did you really pay per share? The answer is your weighted average price, the base for measuring your gains and losses.
The Stock Average Calculator combines two purchases of the same stock into one average cost per share. It also shows your total shares and the total amount invested. It suits investors who buy in steps, though it combines only two buys at a time.
Table of Contents
- What the Calculator Does
- How to Use It, Step by Step
- The Weighted Average Formula
- Worked Example
- How to Read the Results
- Using Your Average Price Wisely
- Limitations and Assumptions
- FAQs About the Stock Average Calculator
What the Calculator Does
The tool card is titled Stock Average Price Calculator (Two Purchases). It has two input panels, First Purchase and Second Purchase. Each panel asks for a share count and a price per share.
- Weighted Average Price: your average cost per share across both buys.
- Total Shares Held: the shares from both purchases added together.
- Total Invested Amount: the dollars spent on both purchases.
- Calculate Average Price button: refreshes the three results after you change the inputs.
The page opens with sample numbers: 100 shares at $150.00 and 50 shares at $120.00. That gives an average of $140.00 on 150 shares and $21,000.00 invested.
How to Use It, Step by Step
- In the First Purchase panel, enter the number of shares in Shares Count.
- Enter what you paid for each share in Price Per Share ($).
- In the Second Purchase panel, enter the shares and price for your next buy.
- Press Calculate Average Price. The results change only when you press it.
- Read the average price, then check the share count and total invested.
To plan a buy, enter shares you are thinking about adding in the second panel. You will see your new average before you place the order.
Have only one purchase so far? Enter 0 in the second Shares Count, and its price can stay blank. With 80 shares at $64.50 alone, the tool shows $64.50, 80 shares, and $5,160.00.
The Weighted Average Formula
A simple average of two prices ignores how many shares you bought at each one. A weighted average gives bigger purchases more influence.
(Shares 1 × Price 1) + (Shares 2 × Price 2)÷Shares 1 + Shares 2=Average Price
- Total invested = (shares 1 × price 1) + (shares 2 × price 2).
- Total shares = shares 1 + shares 2.
- Weighted average price = total invested ÷ total shares, rounded to cents.
Worked Example
Marcus bought 80 shares of a retail stock at $64.50. A few months later the price fell, and he bought 40 more at $52.25.
| Purchase | Shares | Price | Cost |
|---|
| First | 80 | $64.50 | $5,160.00 |
| Second | 40 | $52.25 | $2,090.00 |
| Total | 120 | $60.42 average | $7,250.00 |
The tool shows a Weighted Average Price of $60.42, Total Shares Held of 120, and Total Invested Amount of $7,250.00. A plain average of the two prices would be $58.38, which understates his real cost.
How to Read the Results
Weighted Average Price is your cost per share for the whole position. If the market price is above it, the position shows a gain before fees. If the price is below it, the position shows a loss.
Total Shares Held confirms the size of your position. Check it against your brokerage statement.
Total Invested Amount is the cash spent on shares. Multiply total shares by the current price, then compare the two to see your paper gain or loss.
Using Your Average Price Wisely
Buying more after a drop lowers your average. It also raises your stake in one company. Before adding, decide how much you are willing to risk.
The position size calculator helps you set a share count that fits your risk limit. The risk reward ratio tool compares your stop level with your price target.
Your average price also feeds other measures. Yield on cost uses it with the dividend yield calculator.
Total return on the position fits the return on investment calculator. For yearly growth over several years, try the CAGR calculator. More investing tools are in the finance and business tools hub.
When you sell, capital gains taxes may apply. Brokers usually report cost basis, but keep your own records to compare.
Limitations and Assumptions
- The tool handles only two purchases. Longer buying plans need a few extra steps.
- Commissions and fees are not part of the math.
- It does not handle sales, stock splits, or reinvested dividends.
- Results do not update as you type, so press the button after each change.
- Inputs are checked. First purchase shares must be above 0, and second purchase shares cannot be negative.
- Each price must be at least $0.01. A blank or invalid field shows a message, and the results read N/A.
FAQs About the Stock Average Calculator
What is the average price of a stock I bought twice?
Multiply each share count by its price, then add the two costs. Divide that total by all the shares you own. The result is your weighted average price.
Does averaging down lower my risk?
It lowers your cost per share, but it puts more money into one stock. If the price keeps falling, your loss grows. Averaging down works best within a set risk limit.
Can I use this for ETFs or crypto?
Yes. The math works for anything bought in units at different prices, such as ETFs or crypto. Enter units in Shares Count and the unit price in Price Per Share.
Does the calculator include broker fees?
No. It uses only share counts and prices. To include a fee, divide it by the shares in that purchase and add it to the price.
Can I enter fractional shares?
Yes, the fields accept decimals, such as 2.5 shares. The total shares card shows up to six decimal places. For example, 2.5 shares plus 0.12345 shares shows as 2.62345.
How do I add a third purchase?
Run the first two purchases, then note the total shares and total invested. Divide total invested by total shares for an exact average. Enter that as the first purchase and the new buy as the second.
This calculator gives planning estimates only and is not financial advice. Reviewed for general accuracy by Prof. Dr. Khalil Mudassar, PhD.