Cost Basis Calculator

Calculate your adjusted cost basis and understand how it affects your capital gain or capital loss.

Free educational calculator

Cost Basis Calculator

Estimate your adjusted cost basis using purchase price, fees, reinvested amounts, return of capital, and other adjustments.

Enter your basis information

Total purchase price $ The total amount paid for the investment. Number of shares or units Used to calculate estimated basis per share or unit. Purchase fees $ Optional commissions or acquisition costs. Reinvested dividends or distributions $ Amounts reinvested into additional shares, if applicable. Other increases to basis $ Other valid upward basis adjustments. Return of capital $ Nondividend distributions that reduce basis, if applicable. Other decreases to basis $ Other valid downward basis adjustments.

Basic calculation used: Purchase price + fees + reinvested amounts + other increases − return of capital − other decreases

Important: This calculator provides a simplified educational estimate. Basis rules can differ for inherited property, gifts, stock splits, mergers, employee stock plans, mutual funds, cryptocurrency, partnerships, real estate, depreciation, wash sales, and other situations. Verify your basis using brokerage records, tax documents, and current official guidance.

What Is Cost Basis?

Cost basis is generally the amount you invested in an asset for tax purposes. It usually starts with the purchase price but can change over time because of certain adjustments, such as purchase fees, reinvested dividends, return of capital, stock splits, and other events. Your cost basis is used to determine whether you made a capital gain or capital loss when you sell an investment.

Knowing your correct cost basis is important because an incorrect basis can result in reporting too much or too little gain on your tax return. This calculator provides a simplified estimate to help you understand how adjusted cost basis works using common investment scenarios.

Simple Example

Suppose you purchased stock for $5,000 and paid a $25 commission. Later, you reinvested $200 in dividends. Your adjusted cost basis would be:

Purchase Price: $5,000
Purchase Fees: +$25
Reinvested Dividends: +$200

Estimated Adjusted Cost Basis

$5,225

If you later sold the investment for $7,000, your estimated capital gain would generally be:

$7,000 − $5,225 = $1,775

Frequently Asked Questions

What is cost basis?

Cost basis is generally the amount you invested in an asset after applicable adjustments. It is used to calculate your capital gain or capital loss when the asset is sold.

Why is cost basis important?

Your cost basis determines how much profit or loss you report when you sell an investment. Using the wrong basis may result in reporting an incorrect gain or loss.

What can increase cost basis?

Common increases may include purchase commissions, reinvested dividends, and certain other basis adjustments depending on the investment.

What can decrease cost basis?

Common decreases may include return of capital and certain other adjustments allowed under tax rules.

Does this calculator calculate my taxes?

No. This calculator estimates adjusted cost basis only. It does not calculate the tax you may owe.

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