Accounting for a sole proprietorship comes down to a handful of habits done consistently: choose an accounting method, keep business money out of your personal accounts, log every dollar of income and every deductible expense, send the IRS estimated tax payments four times a year, and report the whole picture on Schedule C when you file your Form 1040. Because the IRS treats you and your business as the same taxpayer, your bookkeeping is what determines what you owe and what you can defend if a return gets questioned.
Pick an Accounting Method
Your accounting method decides when income and expenses appear in your books. The IRS recognizes two: the cash method and the accrual method.1Internal Revenue Service. IRS Publication 538 – Accounting Periods and Methods
Under the cash method, you record income when payment actually lands and expenses when you actually pay them. Invoice a client in December, collect in January, and that income belongs to next year’s return. It maps cleanly to your bank statements, and it gives you a modest amount of timing control: delay an invoice, prepay an expense, and you shift the tax effect across a year boundary.
Under the accrual method, you record income when it’s earned and expenses when they’re incurred, regardless of when the money moves. It shows a truer financial picture at any point in time, but it also means tracking accounts receivable and payable. For most one-person businesses, the extra complexity isn’t worth it.
Most sole proprietors qualify for cash-method accounting. The IRS generally requires accrual only above certain gross receipts thresholds; below roughly $30 million in average annual gross receipts (adjusted for inflation), the cash method is available even if you carry inventory.2Internal Revenue Service. Publication 538 – Accounting Periods and Methods Whichever you choose, use it consistently. Switching later requires IRS approval.
Separate Your Money and Set Up the Books
Open a dedicated business bank account and get a business credit card before you record a single transaction. Commingling personal and business funds is the fastest way to lose deductions in an audit, because the IRS can disallow anything it can’t trace to a clear business purpose. A separate account also gives you a second record of everything: the bank statement itself.
Then choose a bookkeeping system. Single-entry works like a checkbook register: each transaction shows up once as money in or money out. It’s serviceable if your volume is very low, but it can’t track assets, liabilities, or owner equity, and errors are hard to catch.
Double-entry records every transaction in at least two accounts with equal debits and credits. Buy $500 in supplies with cash, and supplies expense goes up $500 while cash goes down $500. The built-in balancing catches mistakes and produces real financial statements. Most accounting software runs double-entry in the background, so you get the accuracy without hand-managing the debits and credits yourself.
Track Business Income
Every dollar the business brings in counts as gross receipts, whether from selling products, performing services, or earning interest on a business account. Record the amount and source of each receipt, and hold onto the supporting documents: deposit slips, invoices you’ve issued, and payment processor records.3Internal Revenue Service. What Kind of Records Should I Keep
If you pay an independent contractor $2,000 or more during the calendar year for services related to your business, you have to report those payments on Form 1099-NEC. That threshold rose from $600 to $2,000 for payments made after December 31, 2025, and it will be adjusted for inflation starting in 2027.4Internal Revenue Service. Form 1099-NEC and Independent Contractors Track those payments as you go so January isn’t spent reconstructing them.
Track Business Expenses
A deductible business expense has to be ordinary (common in your line of work) and necessary (helpful and appropriate for your business). You don’t have to prove it was indispensable, just that it served a legitimate business purpose. Common categories include office supplies, rent, utilities, software, advertising, professional fees, and business insurance.
Vehicle Expenses
Business use of a personal vehicle can be deducted two ways. The standard mileage rate for 2026 is 72.5 cents per mile.5Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents Per Mile The alternative is tracking actual costs (gas, insurance, maintenance, depreciation) and deducting the business-use percentage. Both approaches require a mileage log with the date, destination, business purpose, and miles driven for each trip, kept as you go rather than reconstructed at year-end.
Home Office
To claim a home office deduction, the space has to be used regularly and exclusively for business. A desk that doubles as homework space for the kids won’t qualify. The area also needs to be your principal place of business or a location where you regularly meet clients.6Internal Revenue Service. Topic No. 509, Business Use of Home Calculate it with the simplified method (a flat rate per square foot) or the regular method, which allocates actual home expenses by the percentage of the home used for business.
Equipment and Other Capital Purchases
An asset with a useful life beyond one year, like a computer or a piece of equipment, normally gets capitalized and depreciated over several years. Section 179 lets you deduct the full cost of qualifying assets in the year they’re placed in service, up to an annual limit adjusted for inflation.7Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets Bonus depreciation offers another route to first-year write-off for qualifying property.8Internal Revenue Service. Instructions for Form 4562 For most sole proprietors, one of the two eliminates the need to run multi-year depreciation schedules on ordinary business equipment.
Self-Employed Health Insurance
If you pay your own health insurance and the business shows a profit, you can deduct 100% of premiums for yourself, your spouse, your dependents, and your children under age 27. It’s an above-the-line deduction on Schedule 1 of Form 1040, so you don’t have to itemize to claim it. The deduction can’t exceed net business profit for the year, and you’re not eligible for any month in which you could have joined a subsidized plan through a spouse’s employer. Medical, dental, vision, and Medicare premiums all qualify. The calculation happens on Form 7206.9Internal Revenue Service. Instructions for Form 7206
Owner Contributions and Draws
You can’t pay yourself a salary or issue yourself a W-2 as a sole proprietor.10Internal Revenue Service. 11Internal Revenue Service. Estimated Taxes
Payments are due on the 15th day of the 4th, 6th, and 9th months of your tax year, and the 15th day of the 1st month after your tax year ends. For a calendar-year filer, that’s April 15, June 15, September 15, and January 15 of the following year.12Internal Revenue Service. Publication 509, Tax Calendars If a due date falls on a weekend or holiday, it shifts to the next business day.
The underpayment penalty is avoidable through one of two safe harbors: pay at least 90% of your current year’s tax liability, or pay 100% of what you owed the prior year (110% if your adjusted gross income exceeded $150,000, or $75,000 if married filing separately).13Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty Your first year has no prior-year figure to lean on, so you’ll estimate. Err high. The penalty is essentially interest on what you should have sent, and it accrues quarterly.
File Schedule C With Your 1040
Everything you tracked lands on Schedule C (Profit or Loss From Business), attached to your Form 1040.14Internal Revenue Service. About Schedule C (Form 1040) – Profit or Loss from Business Gross income goes on Line 1, expenses are itemized in Part II, and Line 31 is your net profit or loss. That number flows to your 1040 and drives both income tax and self-employment tax.
Self-Employment Tax on Schedule SE
Net profit from Schedule C is subject to self-employment tax, which funds Social Security and Medicare at a combined 15.3%: 12.4% Social Security plus 2.9% Medicare.15Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) You’re covering both the employee and employer halves that a W-2 worker splits with a company.
The Social Security portion applies only to net earnings up to the annual wage base, which is $184,500 for 2026.16Social Security Administration. What Is the Current Maximum Amount of Taxable Earnings for Social Security The 2.9% Medicare portion has no cap. Calculate the tax on Schedule SE, and deduct half of it as an adjustment to income on your 1040, which lowers your income tax.15Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
Qualified Business Income Deduction
Sole proprietors may also qualify to deduct up to 20% of qualified business income under Section 199A.17Office of the Law Revision Counsel. 26 USC 199A – Qualified Business Income Originally scheduled to expire after 2025, this deduction was extended by the One Big Beautiful Bill Act. The deduction is capped at 20% of taxable income minus net capital gains, and above certain income thresholds, additional limits tied to W-2 wages and business property values can reduce or eliminate it. Certain service-oriented fields (law, consulting, accounting, financial services, among others) face a phaseout once taxable income exceeds specified thresholds. Below those thresholds, the calculation is generally 20% of Schedule C net profit. The deduction lands on the 1040, not on Schedule C, so it doesn’t reduce self-employment tax.
If You Hire Employees
Hiring changes your accounting materially. You have to withhold federal income tax and the employee’s share of Social Security and Medicare from each paycheck, then remit those amounts along with your matching employer share to the IRS.18Internal Revenue Service. Publication 15 (Circular E), Employers Tax Guide You also owe Federal Unemployment Tax (FUTA) at 6% on the first $7,000 of each employee’s wages; a credit of up to 5.4% for state unemployment taxes paid usually reduces the effective FUTA rate to 0.6%.19Internal Revenue Service. Topic No. 759, Form 940, Employers Annual Federal Unemployment Tax Act Return
Payroll adds its own records: hours worked, wages paid, amounts withheld, deposit dates. Most sole proprietors who hire use payroll software or a service, because the penalties for late or incorrect deposits are steep.
Keep Records That Hold Up
The IRS doesn’t require a specific format. Paper ledgers, spreadsheets, and accounting software all qualify. What matters is that the system clearly shows income, expenses, and how you arrived at the figures on your return.20Internal Revenue Service. Recordkeeping If you claim a deduction, you need a record that supports it.
Keep invoices, receipts, bank statements, and canceled checks. For meals, travel, and vehicle use, the IRS expects contemporaneous records made at or near the time of the expense. A mileage log needs the date, destination, purpose, and miles for each trip. Meal receipts should note who was present and the business purpose.
How long you hold records depends on the type:
- Three years is the standard retention period, measured from the date you filed or the return’s due date, whichever is later. This matches the normal IRS audit window.21Internal Revenue Service. How Long Should I Keep Records
- Six years if you failed to report income exceeding 25% of the gross income shown on your return; the IRS has that long to assess additional tax.22Internal Revenue Service. Topic No. 305, Recordkeeping
- Property records for any business asset until the limitations period expires for the year you sell or dispose of it, because you’ll need them to calculate cost basis, depreciation, and gain or loss.21Internal Revenue Service. How Long Should I Keep Records
Electronic storage is allowed, provided the digital copies are legible and retrievable. The system needs an indexing method that lets you find specific documents and an audit trail linking ledger entries back to source documents.23Internal Revenue Service. Revenue Procedure 97-22 In practice, that means organized folders, consistent file names, and the ability to produce a paper copy on request. An unsorted dump of scanned receipts doesn’t meet the standard.