Averaging Stock Calculator
Enter each stock purchase to calculate your weighted average cost per share. Optionally add current market price to see unrealized profit/loss.
What is stock averaging?
Stock averaging means buying shares of the same company at different prices over time. Your true cost basis is not the first price you paid—it is the weighted average of all your purchases. This is useful when you are averaging down after a price drop, or averaging up as a winning position grows.
How the averaging stock calculator works
The calculator adds your total invested dollars and divides by your total shares:
Average Cost Per Share = Total Cost of All Purchases / Total Shares Purchased
- Total Cost = sum of (shares × price) for every lot
- Total Shares = sum of shares from every lot
- Break-even price = your weighted average cost per share
Example: averaging down
Scenario
- Buy 100 shares at $50 = $5,000
- Buy 100 shares at $40 = $4,000
Total shares = 200. Total cost = $9,000. Average cost = $45.00/share.
Even though your first buy was at $50, your new break-even point is now $45 before fees and taxes.
Why investors use this tool
- Track true position cost basis across multiple entries
- Plan exits based on realistic break-even levels
- Compare current price vs average cost quickly
- Avoid mental math mistakes during volatility
Important risk notes
Averaging down is not always wise. If fundamentals are deteriorating, adding more can increase risk in a weak thesis. Always combine cost-basis math with position sizing, stop-loss rules, and portfolio risk management.
- Set a maximum allocation per stock
- Know why you are adding (valuation, catalyst, earnings quality)
- Avoid adding solely because price is lower
- Consider tax implications and trading costs
Frequently asked questions
Does this include brokerage fees?
This version does not include fees automatically. If needed, add fees into your effective share price manually for each lot.
Can I use this for ETFs or crypto?
Yes. The weighted-average method is the same for any asset purchased in multiple lots.
Is average cost the same as fair value?
No. Average cost is your personal cost basis. Fair value is what you believe the asset is intrinsically worth.