Investment tax guide: How to report capital gains

To report capital gains, most taxpayers use Form 8949 to list sales and dispositions, then carry totals to Schedule D to calculate capital gains and losses on the federal income tax return. The main tax factors are holding period, cost basis, taxable income, capital losses, qualified dividends, and whether the net investment income tax applies. Using a secure document management platform, like pdfFiller, helps you accurately prepare these forms online.

A brief summary

• Capital gains tax applies to the profit you make when you sell investments like stocks, bonds, crypto, or real estate.
• The tax rate you pay depends on how long you held the asset: Short-term capital gains (assets held for one year or less) are taxed as ordinary income. Long-term capital gains (assets held for more than one year) are taxed at 0%, 15%, or 20%.
• You can use capital losses to offset your gains: If your losses are greater than your gains, you can deduct up to $3,000 per year ($1,500 if married filing separately) from other income.
• Properly completing Form 8949 and Schedule D is required for reporting realized gains and losses to the Internal Revenue Service.
• pdfFiller helps investors and tax preparers complete, edit, organize, store, and share IRS tax reports in a secure cloud workspace.

Introduction to investment and capital gains taxes

When you sell an investment for a profit, the Internal Revenue Service (IRS) treats that profit as a capital gain, and that gain is generally subject to federal income tax. The rules governing investment taxes cover everything from stocks and mutual funds to real estate and cryptocurrency. Understanding how capital gains are taxed, which IRS forms to use, and how to apply legal tax strategies can help you keep more of what you earn.

This guide walks through the framework for reporting capital gains, from calculating your gain or loss to filing out the correct tax forms. We’ll focus on IRS Form 8949, Sales and Other Dispositions of Capital Assets, and Schedule D, Capital Gains and Losses, since these are the two most important forms for understanding how to report capital gains. We will also explore how pdfFiller helps simplify this process for you.

Disclaimer: This article is for informational purposes only and does not constitute tax, legal, or financial advice. Consult a qualified tax professional or attorney for guidance specific to your situation.

What is capital gains tax, and who has to pay it?

Capital gains tax is a federal tax—and often a state tax—on the profit from selling a capital asset. Capital assets include stocks, bonds, exchange-traded funds (ETFs), mutual funds, real estate, and even collectibles. When you sell an asset for more than your cost basis (what you originally paid, plus adjustments), the difference is a realized capital gain, which is taxable in the year of the sale.

You don’t always owe taxes on investment gains. If your total taxable income is below a certain amount, you might pay a 0% tax rate on long-term gains. However, you generally still need to report any realized gains on your tax return, even if you don’t owe any tax on them.

High-income taxpayers may also need to pay the net investment income tax (NIIT). This is an additional 3.8% tax on investment income, including capital gains, for individuals with a modified adjusted gross income over $200,000 ($250,000 for those married filing jointly). This tax is separate from and in addition to the standard capital gains tax rates.

What is the complete guide to investment taxation?

Investment taxation starts with one basic question: Did you receive investment income, sell investments, or both? Investment income generally includes interest, dividends, capital gains, and other distributions, including mutual fund distributions. IRS Publication 550 explains the tax treatment of investment income and expenses, and when and how to report them on a tax return.

Types of investment income

Here are the most common types of investment income:

1. Interest income from bank accounts, bonds, certificates of deposit, and some government bonds.
2. Dividend income from stocks, mutual funds, and exchange-traded fund holdings.
3. Capital gains from selling assets for more than the adjusted cost basis.
4. Capital losses from selling assets for less than adjusted cost basis.
5. Rental or royalty income, which may also count toward the net investment income tax in some cases.
6. Crypto gains or losses from selling, exchanging, or otherwise disposing of digital assets.

What is the investment tax process like?

Here’s a practical workflow you can follow to calculate and report your investment taxes:

1. Collect Forms 1099-B, 1099-DIV, 1099-INT, 1099-DA, 1099-S, and year-end statements.
2. Separate taxable account activity from tax-advantaged accounts.
3. Identify sales of capital assets.
4. Calculate proceeds, cost basis, adjustments, and holding period.
5. List reportable sales on Form 8949 when required.
6. Transfer totals to Schedule D.
7. Apply capital losses, carryovers, and any capital loss deduction.
8. Review whether net investment income tax, alternative minimum tax, or state taxes may apply.
9. Save records for support in case the Internal Revenue Service asks for documentation.

For more detailed insights, be sure to check out our blog posts about Form 1099-INT, Form 1099-DIV, and our comprehensive guide on all types of Form 1099. These resources will help you better understand reporting requirements and ensure accurate tax filing.

You can use pdfFiller as a document workspace to prepare these records. For example, you can upload Form 8949, Schedule D, brokerage statements, and crypto transaction summaries to fill out and edit them online. pdfFiller also lets you share completed forms with a tax professional, add notes for them, and store everything securely in one account.

Short-term vs. long-term capital gains rates: What’s the difference?

A common question taxpayers ask is “What is the difference between short-term and long-term capital gains?” The answer lies in how long you hold the asset before selling it.

Short-term capital gains apply to assets sold after being held for less than a year. These gains are taxed at your ordinary income tax rate, which ranges from 10% to 37% depending on your total taxable income. For high earners, this can result in a substantially larger tax bill compared to long-term treatment.

Long-term capital gains apply to assets sold after being held for more than a year. The tax rates for these gains are much lower than ordinary income tax rates — just 0%, 15%, or 20%, depending on your income and filing status. Holding assets for longer is one of the most effective ways to lower your federal income tax bill.

Here are the federal long-term capital gains tax rates for the 2026 tax year:

For 2025 long-term capital gains tax rates, see IRS Topic No. 409. It explains how the 20% rate applies to taxable income exceeding the 15% threshold.

State income taxes vary. Some states, like Florida and Texas, have no income or capital gains tax. Others, like California, tax capital gains as regular income at high, graduated rates.

How do you calculate capital gains on stocks?

To calculate capital gains on stocks, subtract your adjusted cost basis from your amount realized on the sale. In plain language, the formula is:

Sales proceeds − adjusted cost basis = capital gain or capital loss

The IRS explains that the basis of stocks or bonds is generally the purchase price plus purchase costs, such as commissions and transfer fees. Adjusted basis may change because of stock splits, nondividend distributions, wash sale adjustments, inherited property rules, or other tax code rules.

Here is a simple example of how to calculate capital gains on stocks:

• You buy 100 shares for $20 per share.
• You pay no commission.
• Your cost basis is $2,000.
• You later sell the shares for $28 per share.
• Your proceeds are $2,800.
• Your realized capital gain is $800.

The $800 gain is considered long-term if you held the shares for more than a year. If you held them for a year or less, it’s a short-term capital gain and is taxed as ordinary income.

It’s important to know the difference between realized and unrealized gains. If your stock’s value goes up but you don’t sell it, that’s an unrealized gain. You generally pay taxes on the profit only when you sell the investment and “realize” the gain. You don’t pay taxes just for holding it.

What is Form 8949, and when do you need it?

Form 8949 (Sales and Other Dispositions of Capital Assets) is the IRS form used to report every individual sale or exchange of a capital asset. You must file Form 8949 if you sold stocks, bonds, ETFs, mutual fund shares, real estate, or cryptocurrency during the tax year.

Your bank, financial institution, or brokerage will typically send you a Form 1099-B by mid-February. This form shows the details of each sale, including the proceeds and cost basis. You’ll use the information from your Form 1099-B to fill out Form 8949.

How to fill out Form 8949

Form 8949 has two parts:

• Part I: Short-term transactions (assets held one year or less)
• Part II: Long-term transactions (assets held more than one year)

Each part is further divided by how the cost basis was reported:

• Box A/D: Basis reported to the IRS by the broker
• Box B/E: Basis not reported to the IRS
• Box C/F: Transactions not reported on Form 1099-B

For each transaction, you enter:

1. Description of the property (e.g., “100 shares XYZ Corp”)
2. Date acquired
3. Date sold
4. Proceeds
5. Cost basis
6. Adjustment codes (if applicable)
7. Gain or loss

The 2025 version of Form 8949 includes new boxes for reporting digital asset transactions. Use boxes G, H, and I for short-term transactions and boxes J, K, and L for long-term transactions involving digital assets. These boxes should be used instead of the existing categories for other types of assets.

A screenshot of IRS Form 8949 in the pdfFiller editor, showing page 1 for reporting short-term capital gains.

After you enter all your transactions, the totals from Form 8949 carry over to Schedule D.

Preparing this form accurately is crucial to avoid IRS penalties. pdfFiller makes it straightforward to complete Form 8949 digitally. You can open the form directly in pdfFiller’s editor, type your entries into each field, review your work before submission, and save or print the completed form. This eliminates handwriting errors and keeps your tax records organized in one place.

What is Schedule D, and how does it work?

Schedule D (Capital Gains and Losses) is the IRS form that summarizes all of your capital gains and losses for the year. It pulls the totals from Form 8949 and calculates your net capital gain or net capital loss.

According to IRS instructions, you must complete Form 8949 before you can fill out lines 1b, 2, 3, 8b, 9, or 10 on Schedule D. While Schedule D is used to calculate your overall gain or loss from transactions on Form 8949, it’s also used to report certain transactions that don’t need to be listed on Form 8949.

Schedule D has three parts:

• Part I: Short-term capital gains and losses (from Part I of Form 8949, plus any short-term carryover losses)
• Part II: Long-term capital gains and losses (from Part II of Form 8949, plus any long-term carryover losses)
• Part III: Summary, where your net gain or loss is calculated

Schedule D (Form 1040) opened in pdfFiller, where users can review, complete, and organize capital gains and losses for short- and long-term investment transactions.

The net result from Schedule D then flows to Line 7 of Form 1040, where it is included in your taxable income. If you have a net capital gain, you may owe tax. If you have a net capital loss, you may be able to deduct it.

What are the cost basis calculation methods?

Cost basis is one of the most important numbers in investment taxes. It affects whether you have a taxable capital gain, a capital loss, or no gain or loss. A wrong cost basis can lead to underreported income, excess tax payments, or IRS notices.

The most common methods include:

• First-In, First-Out (FIFO): Assumes the first shares you bought are the first ones you sold.
• Specific Identification: Allows you to pick exactly which shares you are selling, giving you more control over your tax liability.
• Average Cost: Often used for mutual funds, this method divides the total cost of your shares by the number of shares you own.

Keep records from your broker or financial institution. If the basis reported on Form 1099-B is wrong or incomplete, you may need an adjustment on Form 8949.

How do wash sale rules affect your taxes?

The wash sale rule is an IRS rule that disallows a capital loss deduction if you sell a security at a loss and then buy a “substantially identical” security within 30 days before or after the sale (a 61-day window). It prevents taxpayers from claiming an artificial loss.

If a wash sale applies, you generally cannot deduct the loss right away. Instead, the disallowed loss is added to the cost of the new stock or securities, which adjusts your basis. This usually postpones the loss deduction until you sell the replacement investment.

The wash sale rule applies to stocks, bonds, and ETFs. However, current IRS guidance states that it does not apply to cryptocurrency. This is a key distinction for crypto investors looking to harvest losses at year-end. Before using any tax-loss harvesting strategies, always consult a tax advisor for personalized advice.

The wash sale rule is important for year-end tax planning. While tax-loss harvesting can lower your capital gains taxes, you can’t buy back the same or a very similar investment too quickly without losing the tax benefit. Be sure to check for wash sales across all your accounts, including your spouse’s and retirement accounts, as the rule isn’t limited to a single brokerage.

How does the $3,000 capital loss deduction work?

If your capital losses exceed your capital gains, you can use the net loss to reduce your ordinary income. However, the IRS limits this capital loss deduction to $3,000 per year ($1,500 if married filing separately).

Let’s say you have:

•  $2,000 in short-term capital gains
•  $7,000 in long-term capital losses

This leaves you with a net capital loss of $5,000. You can deduct $3,000 from your other income this year and carry over the remaining $2,000 to a future year.

This rule can affect tax payments and tax planning. A taxpayer with large realized losses may not receive the full tax benefit in the current tax year, but the carryforward can help offset capital gains derived in future years.

You’ll track and report this carryforward on Schedule D each year until it’s fully used.

Qualified dividends vs. ordinary dividends: What is the difference?

Dividend income is a common form of investment income. You will receive a Form 1099-DIV from your broker that reports your dividend income. This form separates ordinary dividends (Box 1a) from qualified dividends (Box 1b). You’ll report this income on Schedule B, then carry it over to your Form 1040.

Ordinary dividends (also called non-qualified dividends) are taxed as ordinary income at your marginal tax rate. These include dividends from REITs, certain foreign corporations, and money market funds.

Qualified dividends are taxed at the same preferential rates as long-term capital gains (0%, 15%, or 20%). To qualify, dividends must be paid by a U.S. corporation or a qualifying foreign corporation, and you must have held the stock for more than 60 days during the 121-day period surrounding the ex-dividend date.

Qualified dividends usually require:

1. Payment by a U.S. corporation or qualified foreign corporation.
2. A dividend type that is not excluded from qualified dividend treatment.
3. Satisfaction of the required holding period.

For common stock, the IRS generally requires that you hold the stock for more than 60 days during the 121-day period that begins 60 days before the ex-dividend date.

How does cryptocurrency taxation work?

According to IRS guidance, the IRS treats digital assets and cryptocurrency as property, not currency. This means that every time you sell, exchange, or use cryptocurrency to buy goods or services, you trigger a taxable capital gain or loss—just as you would with stocks.

To calculate your capital gains or losses, you’ll use the crypto’s fair market value at the time of the transaction. Since crypto prices change quickly, it’s crucial to track your cost basis and transaction dates. These gains and losses are subject to the same short-term and long-term rules as other investments.

For crypto taxes, the capital gain or loss calculation needs detailed records:

• Asset type.
• Date and time acquired.
• Date and time sold or disposed.
• Number of units.
• Fair market value in U.S. dollars.
• Basis.
• Transaction fees.
• Wallet or exchange records.

Reporting crypto taxes

You must report each crypto transaction individually on Form 8949. This includes:

• Selling crypto for fiat currency (e.g., USD)
• Trading one cryptocurrency for another
• Using crypto to purchase goods or services
• Receiving crypto as payment for work (this is taxed as ordinary income, not capital gains)

Mining income and staking rewards are treated as ordinary income at their fair market value on the date received.

Crypto taxes are an area of active regulatory development. The IRS has added a checkbox to Form 1040 specifically asking whether you received, sold, exchanged, or otherwise disposed of digital assets. Answering “yes” requires you to report all relevant transactions.

How do you handle real estate capital gains?

Selling real estate also triggers capital gains tax, but homeowners benefit from a significant exclusion. Under IRS Publication 523, you can exclude up to $250,000 of gain ($500,000 for married filing jointly) from the sale of your primary residence—if you have owned and lived in the home for at least two of the five years before the sale.

Gains above that exclusion are taxable. Investment properties (rental homes, commercial real estate, vacation homes) do not qualify for this exclusion and are fully subject to capital gains tax.

Depreciation recapture is a separate tax issue for rental property owners. If you claimed depreciation deductions while renting the property, the IRS “recaptures” that depreciation when you sell, taxing it at a maximum rate of 25%—even if the rest of the gain qualifies for lower long-term rates.

For accurate tax reporting and to properly calculate your capital gains, ensure to keep the following documents:

1. Closing statements.
2. Purchase price and sale price records.
3. Improvement invoices.
4. Depreciation schedules.
5. Form 1099-S, if issued.
6. Prior-year tax records for rental property.

Final thoughts

Understanding capital gains tax is not optional for investors—it directly affects your after-tax returns. By knowing the difference between short-term and long-term rates, tracking your cost basis, and properly utilizing forms like Schedule D and Form 8949, you can take control of your tax liability. Accurate reporting ensures you stay compliant while maximizing your after-tax money.

For a smoother tax season, keep your IRS forms and records organized. With pdfFiller, you can complete, edit, merge, store, and share Form 8949, Schedule D, and other tax documents from one secure place. Try pdfFiller for free today and prepare your investment tax documents with less paperwork.

Glossary

• Capital assets: Property you own for personal or investment purposes, such as stocks, bonds, real estate, or cars.
• Cost basis: The original purchase price of an investment, adjusted for specific factors, used to calculate your taxable profit or loss.
• Tax liability: The total amount of tax debt you owe to the Internal Revenue Service or local tax authorities.
• Unrealized gains: The profit that exists on paper when an investment increases in value but has not yet been sold.
• Net investment income: The total income derived from investments, including interest, dividends, and capital gains, minus investment expenses.