Taxes for a Garage Business: Self-Employment Tax, Quarterly Payments and the Home Office Deduction

Taxes are the part of a garage business that most people put off until spring, and then they’re scrambling for receipts. The good news is that the basics for a small, one-person business are learnable. This guide covers the federal pieces most garage business owners run into: income tax on your profit, self-employment tax, quarterly estimated payments, the home office deduction and good records.

It’s general information based on IRS and SBA pages as of October 2026. Tax rules change and your situation may differ, so check the current IRS instructions or talk to a tax professional before you file.

How a garage business is usually taxed

Many garage businesses start as sole proprietorships. The SBA notes that sole proprietors report personal and business income on the same return, while corporations are taxed separately from their owners. The IRS says sole proprietors and independent contractors use Schedule C, attached to Form 1040, to figure their business profit or loss.

Your business structure, such as a sole proprietorship, LLC or corporation, changes which forms you file, so if you’ve formed an entity or plan to, ask a tax pro how it’s treated.

All of your sales count, with or without a 1099-K

Selling through Etsy, a payment app or a card reader? The IRS says payment apps and online marketplaces must send Form 1099-K when the payments you received for goods or services exceed $20,000 in more than 200 transactions, and they may send one even below that. Card processors issue one regardless of the amount.

Either way, the IRS is clear that you must report all income from selling goods or services, whether or not you receive a 1099-K. Don’t rely on the forms to tell you what you earned; your own records should.

Self-employment tax

When you work for yourself, nobody withholds Social Security and Medicare taxes from a paycheck, so you pay them through self-employment tax. According to the IRS:

The rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare.
You generally must file and pay it if your net earnings from self-employment are $400 or more.
Social Security tax applies only up to an annual wage base, which changes each year; Medicare tax applies to all net earnings.
An additional 0.9% Medicare tax applies above certain income levels, such as $200,000 for single filers.
You figure the tax on Schedule SE and can deduct the employer-equivalent portion when figuring your adjusted gross income.

Self-employment tax is charged on your net profit, not your total sales. That’s one more reason to track every legitimate business expense.

Quarterly estimated taxes

Because no tax is withheld from your business income, the IRS expects you to pay as you go. Individuals, including sole proprietors, generally must make estimated payments if they expect to owe $1,000 or more when they file.

The four due dates

The IRS divides the year into four payment periods:

January 1 to March 31: due April 15
April 1 to May 31: due June 15
June 1 to August 31: due September 15
September 1 to December 31: due January 15 of the next year

If a date falls on a weekend or legal holiday, a payment made the next business day is on time. You can also pay more often, such as monthly, as long as enough is paid by each deadline.

Avoiding the underpayment penalty

The IRS says you may face a penalty for paying too little by a due date, even if you end up with a refund. Most taxpayers avoid it if they owe less than $1,000 after withholding and credits, or if they paid at least 90% of this year’s tax or 100% of last year’s, whichever is smaller. Higher-income taxpayers have special rules, explained in IRS Publication 505.

How to pay

Individuals can pay through their IRS online account, pay online or by phone, use the IRS app, or mail a voucher from Form 1040-ES.

The home office deduction for a garage workshop

This is the deduction many garage business owners ask about first, and the rules are strict.

Regular and exclusive use

The IRS requires that you use part of your home regularly and exclusively for business. A workspace that’s also where the family car parks or where holiday decorations live generally won’t meet the exclusive-use test for that shared area.

For space inside your home, it generally also has to be your principal place of business, or a place you use substantially and regularly to meet clients. For a separate structure, the IRS says a free-standing studio, garage or barn can qualify if you use it exclusively and regularly for business, and it doesn’t need to be your principal place of business. Special rules apply to space used to store inventory or product samples; IRS Publication 587 covers them.

Simplified method or regular method

You can choose between two ways to figure the deduction:

Simplified method: $5 per square foot of business space, up to 300 square feet, for a maximum of $1,500. There’s no depreciation to track, and mortgage interest and property taxes stay fully deductible on Schedule A if you itemize.
Regular method: deduct the business percentage of actual expenses such as mortgage interest, insurance, utilities, repairs and depreciation, using Form 8829.

Under the simplified method, the deduction can’t exceed your gross income from the business minus other business expenses, and any excess can’t be carried forward. You pick a method on your timely filed return for that year. A detached garage workshop larger than 300 square feet might come out ahead with the regular method, but the extra recordkeeping and depreciation are worth discussing with a tax pro.

Records that make tax time easy

The IRS says you can use any recordkeeping system that clearly shows your income and expenses, and that you must be able to back up the entries, deductions and statements on your return. Supporting documents come from your purchases, sales and other transactions.

A simple system for a garage business:

Open a separate bank account and card for the business so personal and business spending don’t mix.
Save every receipt and invoice, ideally by snapping a photo the same day.
Record sales and expenses weekly in a spreadsheet or bookkeeping app, including platform fees and shipping.
Track mileage for business trips such as supply runs and market days.
Keep a folder for big purchases like saws, lasers or a heat press, since equipment may be depreciated or expensed under special rules.
Keep records as long as you need them to support your return. The IRS says how long depends on the document, and employment tax records should be kept at least four years.

Don’t forget state and local taxes

Federal taxes are only part of the picture. The SBA notes that tax laws vary by location and business structure and that the most common state and local requirements are income and employment taxes. Many states also require sellers of goods to register and collect sales tax, and some cities have local business taxes or licenses. Check your state’s revenue department website and your city or county before your first sale.

If you hire help

Bringing on an employee adds payroll duties. The SBA says employers withhold employee income tax, pay Social Security taxes at the same rate as their employees and report payroll taxes quarterly and annually. An EIN is the first step to setting up payroll. If you’re paying a helper, get advice on whether they’re an employee or a contractor before the first paycheck.

A simple tax routine for your first year

Decide on your structure and keep business money in a separate account.
Set aside a share of each sale for taxes in a savings account; a tax pro can help you pick a percentage.
Put the four estimated tax dates in your calendar.
Measure your workspace and note how it’s used if you plan to claim the home office deduction.
Register for state sales tax if it applies to your products.
Book time with a tax professional before your first return, especially if you bought equipment or formed an LLC.

None of this needs to be complicated. A few minutes each week keeps your numbers clean, makes your quarterly payments predictable and turns tax season into a short checklist instead of a weekend of digging through receipts.

Taxes for a Garage Business: Self-Employment Tax, Quarterly Payments and the Home Office Deduction

How a garage business is usually taxed

All of your sales count, with or without a 1099-K

Self-employment tax