Stock Cost Basis Calculator
Calculate the weighted average cost of a stock position made up of multiple purchases. Enter price and lot quantity for each row; total amount and average cost update instantly.
| # | Price (₺) | × | Lot Quantity | = | Total (₺) | |
|---|---|---|---|---|---|---|
| 1. | × | = | — | |||
| 2. | × | = | — | |||
| 3. | × | = | — | |||
— | × | — | = | — |
Free Cost Basis Calculator for Stocks & Mutual Funds
A cost basis calculator helps you find the weighted average price of multiple purchases of the same stock or mutual fund at different times and prices. Whether you are tracking a single stock, an ETF, or a mutual fund position, knowing your exact cost basis is essential for calculating realized gains and losses. The Borsafolio Cost Basis Calculator is a free, no-signup tool that works for any stock, ETF, or mutual fund — just enter your purchase lots and prices.
Unlike a simple average, a stock average cost basis calculator weights each purchase by the number of shares or lots bought. The formula is: Average Cost Basis = Total Investment Amount / Total Shares. For example, buying 100 shares at $10 and 50 shares at $12 gives an average cost basis of $10.67 — not $11.00. This weighted calculation is critical for accurate tax reporting and portfolio management.
Why You Need a Cost Basis Calculator
You need to know your cost basis to correctly calculate capital gains or losses when selling a position. This is especially important after making additional purchases through dollar cost averaging (DCA), where your average cost changes with each buy. An accurate cost basis calculator for stocks eliminates manual errors and gives you instant results. Many investors also need a cost basis calculator for mutual funds, where reinvested dividends create multiple purchase lots over time.
Professional investors update their stock average cost basis after every transaction. This discipline transforms vague feelings about profit and loss into concrete numbers, leading to better sell decisions and tax optimization. Whether you hold 2 lots or 200, a cost basis calculator gives you the clarity you need for confident investing.
Dollar Cost Averaging (DCA) Calculator
Dollar Cost Averaging means investing a fixed amount at regular intervals regardless of price. When prices drop, you buy more shares; when prices rise, you buy fewer. Over time, DCA tends to produce a lower average cost basis than lump-sum investing at a single price point. Use this cost basis calculator to simulate your DCA strategy and track how your average cost evolves over months or years.
Simply add each periodic purchase as a separate row in the calculator. For example, if you invest $500 monthly into a stock, enter each month's purchase price and lot count. The calculator instantly shows your running stock average cost basis, total shares held, and total amount invested. This makes it easy to see when your DCA strategy is working and when you might want to adjust your approach.
Frequently Asked Questions
How is cost basis calculated for stocks?
Cost basis is calculated as the sum of (Price × Shares) for every purchase, divided by the total number of shares. For example: 100 shares at $10 plus 50 shares at $12 → average cost basis = (10×100 + 12×50) / (100+50) = $1,600 / 150 = $10.67 per share.
Can I use this cost basis calculator for mutual funds?
Yes. This cost basis calculator works for any investment — stocks, ETFs, and mutual funds. For mutual funds with reinvested dividends, add each reinvestment as a separate purchase row with the reinvestment price and share count.
What is the difference between cost basis and average cost?
Cost basis and average cost are often used interchangeably. Cost basis is the total amount paid for a position (price × shares for each lot). Average cost basis is the cost basis divided by total shares — this is what the calculator computes. Both are essential for calculating capital gains taxes.
Is this stock cost basis calculator free?
Yes. The Borsafolio Cost Basis Calculator is completely free with no signup required and no usage limits. Add as many purchase rows as you need to calculate the average cost basis for any stock, ETF, or mutual fund position.