Sources & Citations
Every tax rate, threshold, and calculation on TaxGainsCalc is traced back to a specific government source. This page lists every primary source we cite — the Internal Revenue Code, Treasury Regulations, IRS guidance, and state tax agency publications that form the basis of our work.
We do not rely on secondary sources for dollar figures. When we state a tax rate, we reference the specific IRC section or IRS publication that establishes it. When we display an income threshold, we cite the revenue procedure that announces it. When we show a state rate, we link to the state tax agency's official publication.
If you find a rate or threshold on this site that does not match an official government source, email us at taxgainscalc@gmail.com with the URL and the source document. We will investigate and correct it if we got it wrong. See our Editorial Policy for our full corrections process.
Internal Revenue Code (IRC) Sections
The statute itself — the sections of the Internal Revenue Code that establish the rules, rates, and formulas our calculators implement.
| Source Reference | Topic | Used In |
|---|---|---|
| IRC Section 1(h) | Preferential tax rates for net capital gain (0%, 15%, 20%) | Long-term capital gains calculator, all long-term gain articles |
| IRC Section 1(a)-(d) | Ordinary income tax brackets (10%, 12%, 22%, 24%, 32%, 35%, 37%) | Short-term capital gains calculator, short-term gain articles |
| IRC Section 121 | Exclusion of gain on sale of principal residence ($250,000 single, $500,000 married) | Home sale calculator, home sale tax guide |
| IRC Section 1031 | Like-kind exchange deferral of capital gains | Real estate calculator, 1031 exchange articles |
| IRC Section 1001 | Determination of amount of gain or loss on disposition of property | All calculators, all gain/loss calculation articles |
| IRC Section 1011 | Adjusted basis for determining gain or loss | All calculators, cost basis articles |
| IRC Section 1012 | Cost basis — purchase price as the default basis | Stock calculator, crypto calculator, basis tracking articles |
| IRC Section 1014 | Stepped-up basis for property acquired from a decedent | Inherited property tax guide |
| IRC Section 1015 | Basis of property acquired by gifts and transfers in trust | Gift tax basis articles |
| IRC Section 1016 | Adjustments to basis (depreciation, improvements, amortization) | Real estate calculator, depreciation recapture articles |
| IRC Section 1016(a)(2) | Depreciation deduction adjustments to basis | Real estate calculator, rental property articles |
| IRC Section 1222 | Definitions of short-term and long-term capital gains and losses | All calculators, holding period articles |
| IRC Section 1223 | Holding period rules — when the holding period begins | Holding period articles, wash sale articles |
| IRC Section 1245 | Gain from disposition of depreciable property (depreciation recapture) | Real estate calculator, depreciation recapture articles |
| IRC Section 1250 | Gain from disposition of real property subject to depreciation recapture | Real estate calculator, rental property articles |
| IRC Section 1(h)(1)(E) | 25% maximum rate on unrecaptured Section 1250 gain | Real estate calculator, depreciation recapture articles |
| IRC Section 1411 | Net Investment Income Tax (3.8% surtax on investment income) | NIIT calculator, all articles discussing NIIT |
| IRC Section 1(h)(1)(C) | 28% maximum rate on collectibles gains | Collectibles tax guide, gold/precious metals guide |
| IRC Section 165 | Deduction for losses — capital loss deduction rules | Tax-loss harvesting guide, capital loss carryover guide |
| IRC Section 1091 | Wash sale rule — disallowance of loss on substantially identical securities | Wash sale rule guide, tax-loss harvesting guide |
| IRC Section 165(c) | Limitation on capital loss deduction against ordinary income ($3,000 annual limit) | Capital loss carryover guide, tax-loss harvesting guide |
| IRC Section 1211-1212 | Limitation on capital losses and capital loss carryovers | Capital loss carryover guide |
Treasury Regulations (26 CFR)
The IRS's official interpretation of the Internal Revenue Code — the detailed rules that implement IRC sections.
| Source Reference | Topic | Used In |
|---|---|---|
| 26 CFR Section 1.1-1 | Tax rates on individuals | Short-term capital gains calculator |
| 26 CFR Section 1.61-2 | Gains from dealings in property | All gain calculation articles |
| 26 CFR Section 1.1001-1 | Computation of gain or loss | All calculators |
| 26 CFR Section 1.1011-1 | Adjusted basis | Cost basis articles |
| 26 CFR Section 1.1012-1 | Cost basis of securities | Stock calculator, crypto calculator |
| 26 CFR Section 1.1222-1 | Classification of gains and losses into short-term and long-term | All holding period articles |
| 26 CFR Section 1.1091-1 | Wash sale rule — disallowed loss on substantially identical securities | Wash sale guide |
| 26 CFR Section 1.1411-1 through 1.1411-10 | Net Investment Income Tax regulations | NIIT calculator and guide |
IRS Revenue Rulings & Revenue Procedures
Official IRS guidance on specific tax situations and procedural matters.
| Source Reference | Topic | Used In |
|---|---|---|
| IRS Notice 2014-21 | Virtual currency (cryptocurrency) is property for federal tax purposes | Crypto calculator, crypto tax guide |
| Rev. Rul. 2002-22 | Determination of holding period for securities | Holding period articles |
| Rev. Proc. 2025-34 (Annual inflation adjustments) | 2026 inflation-adjusted income thresholds for capital gains rate brackets, standard deduction, and other amounts | All calculators and rate articles for 2026 tax year |
IRS Publications
IRS official guidance documents explaining tax rules in plain language for taxpayers.
| Source Reference | Topic | Used In |
|---|---|---|
| IRS Publication 550 | Investment Income and Expenses (Including Capital Gains and Losses) | All capital gains articles, stock calculator, mutual funds guide |
| IRS Publication 523 | Selling Your Home — exclusion rules under Section 121 | Home sale calculator, home sale tax guide |
| IRS Publication 544 | Sales and Other Dispositions of Business Property | Real estate calculator, 1031 exchange articles |
| IRS Publication 505 | Tax Withholding and Estimated Tax | Estimated payments guide |
| IRS Publication 17 | Your Federal Income Tax (general reference) | Beginners guide, general tax articles |
| IRS Publication 551 | Basis of Assets | Cost basis articles, inherited property guide |
| IRS Publication 526 | Charitable Contributions (for charitable donation capital gains rules) | Deferral strategies guide |
State Tax Agency Sources
Official publications from each state tax agency used to determine state-level capital gains tax rates.
| Source Reference | Topic | Used In |
|---|---|---|
| California Franchise Tax Board — 2026 Tax Rate Schedules | California personal income tax rates (1% to 13.3%) | State rates page, California-specific articles |
| New York State Department of Taxation — 2026 Tax Rates and Brackets | New York State income tax rates | State rates page |
| New York City Department of Finance — 2026 NYC Tax Rates | New York City income tax surcharge | State rates page |
| All 50 state revenue department official publications | State-specific income tax rates, capital gains treatment, and exclusions | State rates page, state-specific articles |
How to Access These Sources Directly
All primary federal tax sources are available free online. Here are the official websites where you can read the same sources we use:
Internal Revenue Code
law.cornell.edu/uscode/text/26Cornell Law School's Legal Information Institute hosts the full text of Title 26 (the Internal Revenue Code).
Treasury Regulations
ecfr.gov/current/title-26The Electronic Code of Federal Regulations (eCFR) hosts the current Treasury Regulations implementing the IRC.
IRS Revenue Rulings & Notices
irs.gov/irbThe IRS Internal Revenue Bulletin publishes all Revenue Rulings, Revenue Procedures, and Notices.
IRS Publications
irs.gov/forms-instructionsFree download of all IRS Publications, forms, and instructions.