Average Price Calculator
Enter your current quantity and average price, then an additional purchase quantity and price, to calculate the new weighted average price, total quantity, and total cost. The arithmetic is the same across markets and runs entirely in your browser.
Use the average price calculator to combine an existing position with a new purchase and find the resulting weighted average purchase price. It is useful when you buy the same stock, ETF, fund unit, cryptocurrency, or other quantity-based asset at different prices and want one combined cost basis. The calculation is currency-neutral: dollars, won, yen, euros, or another currency all work as long as every price uses the same currency and every quantity uses the same unit.
How to use the average price calculator
- Enter the quantity you already hold and the current average purchase price for that position.
- Enter the quantity you plan to add and the purchase price for the additional units.
- Run the calculation and review the new weighted average price, total quantity, total cost basis, additional cost, and average-price change.
- If you want to compare another purchase scenario, change the additional quantity or price and calculate again.
How the weighted average price calculation works
The calculator first converts each part of the position into cost. Existing cost equals current quantity × current average price, while additional cost equals additional quantity × additional purchase price. The two costs are added together and divided by the combined quantity.
For example, 10 units bought at 100 have a cost of 1,000. Adding 5 units at 80 adds 400 of cost. The combined 15 units therefore have a total cost of 1,400 and a weighted average price of about 93.33 per unit.
A lower additional purchase price can reduce the combined average price, while a higher purchase price can raise it. The size of the change depends on how large the additional quantity is compared with the existing position.
The tool does not automatically include brokerage commissions, taxes, exchange-rate conversion, accrued interest, funding costs, spreads, or differences between the entered price and the actual execution price. If those items matter to your cost basis, account for them separately or incorporate them consistently in your inputs.
Privacy, limitations, and investment notice
All values are calculated locally in your browser and are not uploaded by this tool. This calculator performs arithmetic only. It does not tell you whether averaging down, averaging up, adding to a position, or making any investment is appropriate. A lower average purchase price does not by itself reduce market risk or improve the probability of a profitable outcome. Real account figures can differ because of fees, taxes, currency conversion, corporate actions, fractional-share rules, rounding, and execution prices. Check your broker statement and applicable rules before using the result for an important financial decision.
Average price calculator FAQ
What is a weighted average purchase price?
It is the total cost of all units divided by the total number of units. Larger purchases therefore influence the average more than smaller purchases.
Can I use this for stocks, ETFs, funds, or crypto?
Yes, when the asset can be represented by quantity and purchase price and all entries use consistent units.
Can I calculate averaging down?
Yes. Enter the existing position and a lower additional purchase price to see the resulting average. The tool only shows the arithmetic and does not recommend the trade.
Can I calculate averaging up?
Yes. An additional purchase above the current average price will normally raise the weighted average.
Does it include fees and taxes?
No. Those vary by broker, product, country, and account type.
Can I enter fractional shares or decimal quantities?
Yes, if decimal quantities are meaningful for the asset you are calculating.
Why is the new average not halfway between the two prices?
Because the result is weighted by quantity. It is halfway only when the two quantities are equal.
Does the calculator use live market prices?
No. It uses only the numbers you enter.
Are my holdings or prices sent to a server?
No. Calculation stays in your browser.