Chapter 2: What Counts as Taxable Income

This post is Chapter 2 of 14 of the book Keep More of What You Earn — a plain-English guide to US taxes.

Every February, a client I’ll call Rosa brings me a shoebox. In it: her W-2, a 1099 from a bank, a 1099 from a freelance gig, a letter about unemployment benefits she collected for two months, a statement from her late mother’s estate, and — her face falls as she pulls this one out — a notice that she won $2,000 in a local raffle.

“Which of these do I have to pay tax on?” she asks. “All of it? Some of it? The raffle money — surely not the raffle money?”

Rosa’s shoebox is the perfect map of this chapter. The tax code’s answer to “what counts as income” is broader than most people expect, narrower than some fear, and full of specific exceptions that reward knowing the rules. By the end, you’ll be able to sort any shoebox of your own.

The starting rule: everything counts, unless the law says otherwise

The tax code defines gross income in the broadest possible terms: all income from whatever source derived, unless a specific law excludes it. The default is taxable. Exclusions are special permissions, and each one has its own conditions.

This surprises people because everyday language is sloppier than tax language. “Income” to most of us means “money I earned working.” To the IRS, it means that plus interest, dividends, business profits, rents, royalties, gambling winnings, canceled debts, and yes — raffle prizes. If value flowed to you and no exclusion covers it, it’s income.

So the right question is never “is this income?” It’s always: “is there an exclusion that takes it back out?” Let’s walk through Rosa’s shoebox — and yours — item by item.

Wages and salaries: the obvious one, with hidden corners

Your W-2 wages are the core of gross income for most filers: salaries, hourly pay, overtime, bonuses, commissions, tips. A few corners people miss:

Bonuses and overtime are ordinary income. They’re withheld at a flat 22% federal rate by your employer (up to $1 million), which is just an estimate — the actual tax depends on your total income at filing time.
Tips are income, whether cash or card, and you’re legally required to report them. (For 2026, there’s a new deduction for tip income — up to $25,000 for qualifying workers — but the income itself is still reported first. Details in Chapter 14.)
Employer benefits that look like income but aren’t: your employer’s share of health insurance premiums, up to $50,000 of group term life insurance, and qualified retirement plan contributions are excluded by specific laws. That’s why your W-2 Box 1 (taxable wages) is usually less than your actual salary.
The flip side: some “benefits” are taxable — personal use of a company car, gym memberships paid by the boss, and cash awards all show up in Box 1.

Interest, dividends, and the quiet money

Rosa’s bank 1099-INT showed $340 in savings interest. Taxable? Yes — ordinary interest is ordinary income, taxed at your regular bracket rates. There’s no minimum: even $12 of interest is technically reportable (banks just aren’t required to send you a form under $10).

Dividends are subtler, because the tax code splits them in two:

Ordinary dividends — taxed like wages, at your bracket rates.
Qualified dividends — taxed at the lower capital-gains rates (0%, 15%, or 20%), provided you held the stock long enough. Most dividends from US corporations and many foreign ones qualify.

Business and freelance income: revenue is not income

Rosa’s 1099-NEC showed $8,000 for freelance bookkeeping. Here’s the critical distinction: the $8,000 is not her income — her profit is. Self-employment income means revenue minus deductible business expenses. If she spent $1,200 on software, mileage, and supplies, her taxable business income is $6,800.

This is why freelancers who don’t track expenses overpay: every undocumented $100 of expenses is $100 of phantom profit you’re taxed on. At a 22% income tax rate plus 15.3% self-employment tax, that’s roughly $37 per $100 left on the table.

Investment gains: timing changes the tax

Sell a stock, a fund, or crypto for more than you paid, and the profit — the capital gain — is income. But how long you held it changes the rate dramatically:

Short-term (one year or less): taxed as ordinary income, at your bracket rate.
Long-term (more than one year): taxed at the special capital-gains rates — 0%, 15%, or 20% depending on your taxable income. For 2026, a single filer pays 0% on gains up to $49,450 of taxable income, 15% up to $545,500, and 20% above that. (Married filing jointly: 0% up to $98,900.)

Watch what holding period does to the same $10,000 gain for someone in the 22% bracket: sold after 11 months: $10,000 × 22% = $2,200 tax. Sold after 13 months: $10,000 × 15% = $1,500 tax. Two months of patience: $700.

Losses work in reverse: capital losses offset capital gains, and up to $3,000 of net loss per year can offset ordinary income like wages.

Rents, royalties, and the “other income” line

Rental income is taxable — but again, it’s net rental income: rent collected minus mortgage interest, taxes, insurance, repairs, and depreciation. Royalties (books, music, patents, mineral rights) are ordinary income. And then there’s the famous Line 8z, “other income”: the tax code’s junk drawer — gambling winnings, game-show prizes, canceled debt (forgiven debt is generally income — the lender sends you a 1099-C), jury duty pay, and Rosa’s $2,000 raffle prize. Sorry, Rosa. The raffle money is income.

Retirement money: taxed when it comes out (usually)

Traditional 401(k) and IRA contributions went in pre-tax. The deal was always deferral, not exemption: withdrawals in retirement are taxed as ordinary income.

Two exceptions to know:

Roth accounts reverse the deal: no deduction going in, but qualified withdrawals (after age 59½ and five years) are completely tax-free. Chapter 10 runs the full comparison.
Already-taxed contributions (“basis”) come out tax-free. If you ever made non-deductible IRA contributions, that portion isn’t taxed twice — you track it on Form 8606, every year, until it’s all out.

Unemployment, Social Security, and alimony: the special cases

Rosa collected $4,800 in unemployment for two months. Fully taxable as ordinary income. You can elect to have 10% withheld from unemployment checks; most people don’t, and then April hurts. If you’re ever on benefits, make that election.

Social Security benefits occupy a strange middle ground: the formula taxes none, half, or up to 85% of your benefits depending on your other income. The thresholds — $25,000 for single filers, $32,000 for joint — were set in 1993 and never indexed for inflation, so every year more retirees drift into taxable territory.

Alimony follows a date line: for divorce agreements executed after December 31, 2018, alimony is not income to the recipient and not deductible by the payer. Older agreements generally keep the old rules unless modified. Child support was never income and never deductible, under any agreement.

What’s NOT income: the exclusion list

Now the good news — the permissions that take things back out. Each of these is excluded by a specific law:

Gifts and inheritances. Rosa’s distribution from her mother’s estate? Not income. For 2026, anyone can give up to $19,000 per recipient per year with no gift-tax paperwork at all; the lifetime estate/gift exemption is $15 million per person ($30 million for a couple).
Life insurance payouts. Death benefits paid by reason of death are excluded. (Interest that accumulates on the payout afterward is taxable.)
Municipal bond interest. Interest on state and local government bonds is exempt from federal tax.
Qualified Roth withdrawals — the single most valuable exclusion most readers will ever use.
Health insurance benefits and HSA withdrawals for medical expenses.
Child support received — never income.
A few oddballs: workers’ compensation, compensatory damages for physical injury, and the gain on selling your main home (up to $250,000 single / $500,000 joint, if you owned and lived there 2 of the last 5 years).

Above-the-line adjustments: deductions you get even if you don’t itemize

Adjustments to income (the “above-the-line” deductions) are available to everyone, whether you itemize or not. They reduce your AGI, which makes them doubly valuable. The main ones:

Traditional IRA contributions (up to $7,500 for 2026, or $8,600 if you’re 50+), subject to income limits if you have a workplace plan. Chapter 10 covers the phaseouts.
HSA contributions — up to $4,400 self-only or $8,750 family for 2026. The rare triple tax break: deductible going in, tax-free growth, tax-free withdrawals for medical costs. Chapter 11.
Student loan interest — up to $2,500 per year on qualified loans, subject to income phaseouts. Interest only, not principal.
Half of self-employment tax. If you’re self-employed, the employer-equivalent half of your 15.3% SE tax comes off here. Chapter 12.
Educator expenses — teachers and instructors can deduct out-of-pocket classroom costs.

Why AGI is the most important number on your return

Almost nobody talks about AGI at dinner parties, but tax professionals obsess over it, because dozens of limits, phaseouts, and credits key off it: the medical expense deduction only counts costs above 7.5% of AGI; education credits, the Saver’s Credit, and IRA deduction eligibility all phase out across AGI ranges; the child and dependent care credit rate slides with AGI; even the new 2026 senior bonus deduction ($6,000 for taxpayers 65+) phases out above $75,000/$150,000 of MAGI.

So a $4,400 HSA contribution doesn’t just save you $4,400 × your marginal rate in tax. If it drops your AGI below a phaseout threshold, it can unlock or enlarge credits worth thousands more.

Key takeaways

The default is taxable. Gross income means all income from whatever source — the question is always whether a specific exclusion takes it out.
Business and rental income means profit, not revenue. Track expenses relentlessly; every undocumented dollar is taxed as if it were profit.
Holding period changes investment tax. Long-term gains get the 0%/15%/20% rates; short-term gains are taxed like wages. Patience is a tax strategy.
Gifts, inheritances, life insurance, muni-bond interest, and qualified Roth withdrawals are excluded. Know them before you need them.
Watch the special cases: unemployment is fully taxable, up to 85% of Social Security can be taxable (on thresholds frozen since 1993), and post-2018 alimony is tax-neutral.

Next: Chapter 3 — Deductions vs. Credits.