How to Pay Taxes When Paid in Cash: Schedule C, SE Tax, and Estimates

If you’re paid in cash, you pay taxes on it the same way any self-employed person does: track every dollar you receive, report your net earnings on Schedule C with your Form 1040, calculate self-employment tax on Schedule SE, and send quarterly estimated payments to the IRS if you expect to owe $1,000 or more for the year. Cash income is taxable whether or not anyone sends you a 1099, and the reporting duty is yours from the first dollar.1Internal Revenue Service. Are You Making Extra Cash Selling Stuff or Providing a Service?

When You Have to Report Cash Income

The threshold most cash earners run into is low. If your net earnings from self-employment reach $400 in a year, you owe self-employment tax and must file a return.2Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) Net means gross receipts minus deductible business expenses. Earn $1,200 mowing lawns with $900 in gas, supplies, and other qualifying costs, and your net is $300, so the self-employment filing trigger doesn’t apply. Cross $400 net, and it does.

Ignore the $600 number you may have heard. That’s the level at which a business paying you has to issue a Form 1099-NEC. It has nothing to do with whether the income is taxable. Do $500 jobs for five different clients and none of them will send you a 1099, but you still owe tax on the full $2,500.1Internal Revenue Service. Are You Making Extra Cash Selling Stuff or Providing a Service? The payment method also doesn’t change anything. Cash, check, Venmo, PayPal, or barter, the tax treatment is identical.

A quick note on tips, which often come alongside cash work: cash tips, charged tips your employer passes to you, and your share of a tip pool are all taxable. You have to report tips to your employer if they total $20 or more in a single month from that job.3Internal Revenue Service. Tip Income Is Taxable and Must Be Reported Tips under $20 in a month don’t get reported to your employer but still count as income on your return.

Keep Records As You Go

Cash doesn’t leave a paper trail on its own, so build one yourself. For each payment, write down the date, the amount, who paid you, and what it was for. A spreadsheet, accounting software, or a notebook works, as long as you’re consistent and you record it when it happens, not in April.

For business expenses you want to deduct, keep receipts. If you pay cash and don’t get a receipt, IRS guidance is to write down what you bought, from whom, and the business purpose at the time of the payment. Bank and credit card statements can support expenses you paid electronically, as long as the statement shows the amount, payee, and posting date.4Internal Revenue Service. Publication 583, Starting a Business and Keeping Records

Hold on to tax records for at least three years from the date you filed. Keep them six years if there’s any chance you underreported gross income by more than 25%, since that’s how far back the IRS can look in that situation.

Where Cash Income Goes on Your Return

Freelance, Gig, and Independent Work: Schedule C

Cash you earn as a freelancer, independent contractor, gig worker, or sole proprietor goes on Schedule C. Total gross receipts go on Line 1, and deductible business expenses appear in Part II.5Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025) – Section: General Instructions The difference is your net profit, and that number flows into the rest of your Form 1040.

Common deductions for cash-based work include advertising, business mileage, phone and internet, supplies, and a home office if you use a dedicated space regularly and exclusively for work. Each one needs documentation, which is why the record-keeping matters.

Hobby Income: Schedule 1, Line 8

If your cash-earning activity isn’t really a business, meaning you don’t have a profit motive, don’t keep proper books, and don’t depend on the income, the IRS may treat it as a hobby.6Internal Revenue Service. Here’s How to Tell the Difference Between a Hobby and a Business for Tax Purposes Hobby income still gets reported, on Schedule 1 (Form 1040), Line 8, but you can’t deduct expenses against it.7Internal Revenue Service. Know the Difference Between a Hobby and a Business If your activity is genuinely a business, treat it as one from the start and file Schedule C.

Unreported Tips: Form 4137

Tips you didn’t report to your employer during the year go on Form 4137, which calculates the Social Security and Medicare tax owed on them. That amount gets added to your return.8Internal Revenue Service. About Form 4137, Social Security and Medicare Tax on Unreported Tip Income

Self-Employment Tax: The Extra 15.3%

Cash income you report on Schedule C is subject to self-employment tax on top of regular income tax. This covers your Social Security and Medicare contributions. An employer normally pays half and withholds the other half from your paycheck; when you’re self-employed, you pay both halves yourself.

The rate is 15.3% of your net earnings: 12.4% for Social Security and 2.9% for Medicare.2Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) The Social Security portion only applies to earnings up to $184,500 in 2026.9Social Security Administration. Contribution and Benefit Base The Medicare portion has no cap. If your net self-employment income tops $200,000 (single filers), an additional 0.9% Medicare tax applies to the amount above that threshold, calculated on Form 8959.10Internal Revenue Service. 2025 Instructions for Form 8959

You compute all this on Schedule SE and report it on your Form 1040. You can then deduct half of your self-employment tax when calculating your adjusted gross income, whether or not you itemize.11Internal Revenue Service. Topic No. 554, Self-Employment Tax

Pay As You Go: Quarterly Estimated Taxes

With no employer withholding from a cash paycheck, you’re expected to pay your taxes throughout the year. The IRS requires estimated payments if you expect to owe $1,000 or more when you file, after any withholding and refundable credits.12Internal Revenue Service. Estimated Taxes

Payments are due four times a year:

  • April 15, for income earned January through March
  • June 15, for April and May
  • September 15, for June through August
  • January 15 of the following year, for September through December

If a due date falls on a weekend or legal holiday, it moves to the next business day.12Internal Revenue Service. Estimated Taxes Pay through IRS Direct Pay, the Electronic Federal Tax Payment System (EFTPS), by mail with Form 1040-ES vouchers, or through the IRS2Go app. Anything still owed after your quarterly payments is due when you file the annual return.

The Safe Harbor

You avoid an underpayment penalty if your total payments for the year meet one of two benchmarks:

  • 90% of your current year’s tax liability, or
  • 100% of last year’s total tax, whichever is smaller

If your prior-year adjusted gross income was over $150,000 ($75,000 if married filing separately), the prior-year figure rises to 110%.13Internal Revenue Service. Instructions for Form 2210 (2025) The prior-year safe harbor is useful during an unpredictable first year of self-employment. Owe $2,000 last year, pay at least $2,000 in estimated tax this year, and you’re protected from the underpayment penalty even if your actual liability is higher.

What It Costs to Skip Reporting

The IRS matches 1099s against returns and can audit bank deposits that don’t square with what you reported. If underreporting turns up, the penalties stack:

Interest also accrues on unpaid tax from the original due date, compounding daily. The IRS underpayment rate adjusts quarterly and was 7% for the first quarter of 2026.18Internal Revenue Service. Quarterly Interest Rates

The audit window matters too. The IRS normally has three years from your filing date to audit a return, but omit more than 25% of your gross income and that stretches to six.19Office of the Law Revision Counsel. 26 U.S. Code 6501 – Limitations on Assessment and Collection Never file at all and there’s no time limit; the IRS can come after you whenever it wants.