What is the average cost per share?

It is the total amount you invested divided by the total number of shares you own. For example, if you bought 10 shares at $50 and 20 shares at $40, your total cost is $1,300 and total shares is 30, giving an average of $43.33 per share.

What is dollar-cost averaging (DCA)?

Dollar-cost averaging is an investment strategy where you buy a fixed dollar amount of a stock at regular intervals, regardless of price. Because you buy more shares when the price is low and fewer when it is high, your average cost per share is typically lower than the average market price over the period.

Does this tool account for commissions or fees?

The calculator uses the price per share you enter. If you want to include commissions, add the commission to the total cost before calculating: price per share = (shares × price + commission) ÷ shares.

How is unrealized gain or loss calculated?

Unrealized gain or loss = (current price − average cost) × total shares. A positive result means you are currently profitable; negative means you are at a loss. This is unrealized because you have not sold the shares yet.

Can I use this for ETFs, mutual funds, or crypto?

Yes. The math is identical for any asset measured in units (shares, coins, tokens). Simply enter each purchase lot with the quantity and price paid.

Stock Average Calculator

Name: Stock Average Calculator
Availability: InStock
Author: Nham Vu

Enter each stock purchase — shares bought and price paid — to calculate your average cost per share and total investment.

Purchase Lots

Current Market Price (optional)

Used to calculate unrealized gain / loss.

Enter at least one purchase to see your average cost.

Average Cost Per Share

$0.00

Total Shares

Total Invested

$0.00

Purchases

Purchase Breakdown

#	Shares	Price	Amount	Weight

Summary

Enter each stock purchase — shares bought and price paid — to calculate your average cost per share and total investment.

How it works

Enter the number of shares and the price per share for your first purchase.
Click "Add Purchase" to add more buy lots at different prices.
Results update automatically as you type.
The average cost per share is your total cost divided by total shares.
Enter the current market price to see your unrealized gain or loss.
Click the trash icon to remove any purchase row.

Use cases

Tracking the blended cost basis after dollar-cost averaging into a stock.
Calculating how a new purchase changes your average price.
Determining break-even price after buying a dip.
Comparing average cost against current market price to gauge profitability.
Planning how many shares to buy at what price to reach a target average.
Tax planning — knowing your average cost basis for capital gains calculations.

Frequently Asked Questions

Last updated: 2026-06-18 · Reviewed by Nham Vu