What a Side Hustle Actually Costs in Taxes: 1099 Basics With IRS Sources

The most expensive sentence in side-hustle world is "it was cash, so it doesn't count." It counts. It has always counted. And the guys who learn that in April, staring at a number they didn't save for, tend to quit hustles that were actually working.

This is the plain-English version of how US taxes hit a side hustle in 2026, with the primary sources linked so you can verify every claim. One thing before the math: I'm a guy with a spreadsheet, not a CPA. This article is education, not advice — the IRS pages linked here are the authority, and a real tax pro is worth every dollar the year your situation gets complicated.

The rules that actually matter

Rule one: income is taxable whether or not a form shows up. Paper or no paper, mowing money and flip profits are gross income. The forms are for the IRS's information, not permission slips for you to owe.

Rule two: the $400 line. If your net self-employment earnings — profit, not revenue — hit $400 in a year, you must file and you owe self-employment tax. That's per the IRS's Self-Employed Individuals Tax Center. Below $400 net, no SE tax, though the income can still be subject to regular income tax.

Rule three: know what the 2026 form thresholds are — and what they aren't. Two big changes came out of the 2025 tax law (the One Big Beautiful Bill Act): businesses that pay you as a contractor now issue a 1099-NEC at $2,000 in a year (it was $600 for ages), and payment apps and marketplaces issue a 1099-K only past $20,000 and 200 transactions — Congress restored the old threshold after years of back-and-forth. The IRS explains the 1099-K rules on its Understanding your Form 1099-K page. Read those thresholds correctly: they changed who mails you paperwork. They changed nothing about what's taxable. See rule one.

Rule four: you pay two taxes, not one. Employees split Social Security and Medicare with their employer and never see the employer half. Self-employed, you're both halves: 15.3% (12.4% Social Security + 2.9% Medicare), applied to 92.35% of your net profit, on top of ordinary income tax at whatever bracket your total income puts you in. This is the number that ambushes people. Half of the SE tax is deductible against your income tax, which softens it slightly.

A worked example: the $8,000 hustle year

Say you ran a pressure-washing season like the one in my startup ledger and grossed $8,000. Single filer, day job in the 12% bracket. Illustrative round numbers — your rates, state, and situation will differ:

That ~25% is why the set-aside rule exists: move 25–30% of every payment into a separate account the day it lands, and tax season becomes a transfer instead of a crisis. If your day-job income puts you in the 22% bracket, set aside 30–35%.

Deductions: the legal ones, used properly

Every legitimate business expense reduces both taxes. The big ones for hustle guys: equipment and tools (often deductible in full the year you buy them under Section 179/bonus rules), supplies and consumables, the business-use share of your phone, software and platform fees, insurance premiums, and mileage — which for a driving-heavy hustle like a mowing route is frequently the largest deduction of all. Log it contemporaneously: date, miles, purpose. An app or a $2 notebook both work; memory in April does not.

Two cautions. The home-office deduction requires a space used exclusively and regularly for the business — a desk that's also the gaming rig doesn't qualify, and it's a common audit tripwire. And deducting expenses year after year against a hustle that never turns a profit invites the hobby-loss rules; the IRS eventually wants to see that you're actually trying to make money.

The state and local layer

Federal is the big bill, not the whole bill. Most states tax your hustle profit as ordinary income — anywhere from zero (Texas, Florida, Tennessee and the other no-income-tax states) to close to double digits in California — and it rides on the same Schedule C numbers, so the bookkeeping does double duty. Two localized surprises worth checking before your first season, using your own state and city's official sites: municipal income taxes (Ohio guys learn this one fast — many cities tax net profits earned inside city limits, sometimes in whichever city the driveway you washed sits in), and sales tax on services, which a minority of states apply to things like detailing or landscaping, requiring you to register, collect, and remit. Selling goods — flipped furniture, parts — triggers sales-tax registration in most states once you're operating as a business. None of this is hard; all of it is much easier to set up in March than to untangle in an audit letter.

Quarterly payments and the easy workaround

If you'll owe $1,000+ in tax on hustle income, the IRS expects payments through the year — due roughly April 15, June 15, September 15, and January 15. Miss them and you'll owe an underpayment penalty on top. The workaround almost nobody uses: if you also have a W-2 job, file a new W-4 and have extra tax withheld from your paycheck instead. Withholding is treated as paid evenly through the year, it's one form instead of four payments, and it papers over a lumpy hustle season automatically.

Your 20-minute setup

Quick answers

Do I need an LLC to deduct expenses? No. A sole proprietor filing Schedule C deducts the same expenses. An LLC is about liability separation, not a tax discount — single-member LLCs are taxed identically by default.

My buyer paid cash and there's no record. Still taxable? Yes. Records protect you — they're how you prove your expenses, too. Flippers: your cost basis in everything you sell is deductible, but only if you logged it. My flipping plan includes the deal log for exactly this reason.

Is selling my own used stuff taxable? Selling your old couch for less than you paid it isn't — that's a personal loss, not income. Buying couches to resell is a business. The line is intent, and your listing history makes it obvious.