Average cost engine
Enter your buy lots
Lot
Buy price
Quantity
Amount
Action
Stock Average Calculator
Add buy price and quantity for each purchase, then see total shares, total investment, average price, and unrealized gain or loss instantly.
How the average share price is calculated
The formula is total investment divided by total shares. For example, buying 100 shares at 250 and 200 shares at 275 gives an average price of 266.67.
- Runs locally in your browser without storing your entries.
- Adds multiple purchase lots in the order you enter them.
- Shows total quantity, total invested amount, average price, and optional profit or loss.
This is a calculation helper, not investment advice. Brokerage, taxes, fees, and currency conversion are not included.