Accounting for a sole proprietorship comes down to a short list of habits: choose an accounting method, keep business money in its own accounts, record every dollar in and out against the categories you’ll use on Schedule C, send the IRS estimated tax payments four times a year, and file Schedule C with your Form 1040 at year-end. Because you and the business are the same taxpayer, the quality of your bookkeeping determines whether tax season is a thirty-minute reconciliation or a weekend of forensic work.
Pick a Cash or Accrual Method
Your accounting method decides when income and expenses hit your books. The IRS recognizes two: cash and accrual.1Internal Revenue Service. IRS Publication 538 – Accounting Periods and Methods
Under the cash method, you record income when the money actually arrives and expenses when you actually pay them. An invoice sent in December but paid in January belongs to next year’s return. This matches your bank statements line for line and gives you some control over timing: you can delay an invoice or prepay a January bill to shift the deduction into the current year.
The accrual method records income when you earn it and expenses when you incur them, whether or not cash has moved. It gives a more accurate picture of what you’re owed and what you owe, but it adds complexity most one-person businesses don’t need.
Most sole proprietors qualify for cash and should use it. The IRS generally requires accrual only once average annual gross receipts exceed a threshold (around $30 million, adjusted for inflation), and you can stay on cash even with inventory below that line.2Internal Revenue Service. Publication 538 – Accounting Periods and Methods Whichever you pick, use it consistently. Switching methods later requires IRS approval.
Separate the Money and Choose a Bookkeeping System
Open a dedicated business checking account and get a business credit card before you record a single transaction. Commingling personal and business money is the fastest way to destroy your records, and in an audit the IRS can disallow deductions it can’t trace to a clear business purpose. A separate bank statement also doubles as a secondary record of every transaction.
Then pick how you’ll record those transactions. Single-entry bookkeeping works like a checkbook: each transaction appears once as money in or money out. It’s workable if you have very few transactions, but it can’t track assets or liabilities, and errors are hard to catch.
Double-entry bookkeeping records every transaction in at least two accounts with equal debits and credits. Buy $500 in supplies with cash and supplies expense goes up by $500 while cash goes down by $500. The balancing requirement catches mistakes early and lets you produce a real balance sheet and income statement. Almost all accounting software uses double-entry under the hood, so you get the accuracy without having to think about debits and credits yourself.
Record Your Income
Every dollar the business brings in counts as gross receipts, whether from products, services, or interest on a business account. Track the amount, source, and date of each receipt no matter how it arrives: cash, check, electronic transfer, or card.3Internal Revenue Service. What Kind of Records Should I Keep Deposit slips, issued invoices, and payment processor reports are your supporting documents.
If you pay an independent contractor $2,000 or more during the calendar year for business-related services, you’ll owe them a Form 1099-NEC. That threshold rose from $600 to $2,000 for payments made after December 31, 2025, and will be inflation-adjusted starting in 2027.4Internal Revenue Service. Form 1099-NEC and Independent Contractors Track contractor payments as you go so you aren’t reconstructing them in January.
Record Your Expenses
A deductible expense must be both ordinary (common in your line of work) and necessary (helpful and appropriate). You don’t have to prove it was indispensable, only that it served a legitimate business purpose. Office supplies, rent, utilities, software subscriptions, advertising, professional fees, and business insurance are typical categories.
Vehicle Use
If you drive a personal vehicle for business, you can either take the standard mileage rate, which is 72.5 cents per mile for 2026, or deduct the business percentage of your actual costs for gas, insurance, maintenance, and depreciation.5Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents Per Mile Either way, you need a contemporaneous mileage log: date, destination, business purpose, and miles. The IRS expects these entries kept as you drive, not pieced together from memory in April.
Home Office
A home office deduction requires space used regularly and exclusively for business. A desk tucked in the living room that doubles as homework space won’t qualify. The area must be your principal place of business or a spot where you regularly meet clients.6Internal Revenue Service. Topic No. 509, Business Use of Home You can use the simplified method (a flat rate per square foot) or the regular method, which allocates actual home expenses by the business percentage of your home.
Equipment and Other Capital Purchases
When you buy something with a useful life of more than a year, like a computer or furniture, you normally capitalize the cost and recover it through depreciation over several years. Two provisions usually let a sole proprietor skip that: Section 179 allows a full first-year deduction for qualifying assets up to an annual limit,7Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets and bonus depreciation offers another path to write off qualifying property in year one.8Internal Revenue Service. Instructions for Form 4562 Between them, most ordinary business equipment purchases can be deducted upfront.
Self-Employed Health Insurance
If you pay your own health insurance premiums and the business shows a profit, you can deduct 100% of the premiums for yourself, your spouse, your dependents, and your children under age 27. The deduction comes out above the line on Schedule 1 of Form 1040, so you get it without itemizing. It can’t exceed your net business profit, and you lose eligibility for any month you could have joined a subsidized plan through a spouse’s employer. Medical, dental, vision, and Medicare premiums all qualify. The calculation goes on Form 7206.9Internal Revenue Service. Instructions for Form 7206
How You Pay Yourself
You can’t put yourself on payroll or issue yourself a W-2.10Internal Revenue Service. 11Internal Revenue Service. Estimated Taxes
Payments fall on the 15th day of the 4th, 6th, and 9th months of your tax year and the 15th day of the 1st month after it 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 When a due date lands on a weekend or holiday, it shifts to the next business day.
You avoid the underpayment penalty by hitting one of the safe harbors: pay at least 90% of your current year’s tax, or 100% of what you owed last year (110% if your prior-year 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 you have no prior-year number to lean on, so estimate your profit and overpay slightly. The penalty is essentially interest on the shortfall, charged quarter by quarter.
File Schedule C With Your 1040
All of your tracking ends up 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, deductible expenses in Part II, and the net profit or loss on Line 31. That bottom-line number flows to your 1040 and drives both your income tax and your self-employment tax.
A net loss can offset other personal income like wages or investment earnings. If losses are large, the excess business loss limitation may cap how much you can deduct this year, with the overage carried forward as a net operating loss.15Internal Revenue Service. Excess Business Losses
Self-Employment Tax
Your Schedule C net profit is also hit with self-employment tax, which funds Social Security and Medicare at a combined 15.3%: 12.4% Social Security plus 2.9% Medicare.16Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) You’re covering both halves of what an employer and employee would split.
Social Security applies only up to the annual wage base, which is $184,500 for 2026.17Social Security Administration. What Is the Current Maximum Amount of Taxable Earnings for Social Security Medicare has no cap. Calculate it all on Schedule SE, and remember to deduct half of the self-employment tax as an adjustment to income on your 1040, which lowers your regular income tax.
Qualified Business Income Deduction
Sole proprietors may deduct up to 20% of qualified business income under Section 199A.18Office of the Law Revision Counsel. 26 USC 199A – Qualified Business Income It was originally set to expire after 2025 and was extended by the One Big Beautiful Bill Act. The deduction is capped at 20% of taxable income minus net capital gains. Higher-income filers face additional limits tied to W-2 wages and business property, and certain service fields (law, consulting, accounting, financial services) phase out above specified income thresholds. Below those thresholds, the math is straightforward: 20% of your Schedule C net profit. The deduction sits on your 1040, not on Schedule C, so it doesn’t reduce your self-employment tax.
If You Hire Employees
Hiring changes your accounting substantially. You become responsible for withholding federal income tax plus the employee’s share of Social Security and Medicare, remitting those amounts along with your matching employer share.19Internal 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, usually reduced to an effective 0.6% after the credit for state unemployment taxes paid.20Internal Revenue Service. Topic No. 759, Form 940, Employers Annual Federal Unemployment Tax Act Return
Payroll adds its own recordkeeping layer: hours worked, wages paid, taxes withheld, deposit dates, and quarterly and annual returns. Penalties for late or incorrect deposits are steep, which is why most sole proprietors with employees pay for payroll software or a service rather than handle it by hand.
Keep the Records That Back It All Up
The IRS doesn’t dictate a format. Paper ledgers, spreadsheets, and accounting software all qualify as long as your system clearly shows income, expenses, and how you got to the numbers on your return.21Internal Revenue Service. Recordkeeping The burden of proof is on you: if you claim a deduction, you need the record to support it.
Keep invoices, receipts, bank statements, and canceled checks. For meals, travel, and vehicle use, the IRS expects contemporaneous notes made at or near the time of the expense. A mileage log needs date, destination, purpose, and miles. A meal receipt should note who you met with and why.
How long to hold onto records depends on the type:
- Three years is the standard retention period for most tax records, measured from the filing date or the return’s due date, whichever is later. This matches the normal IRS audit window.22Internal Revenue Service. How Long Should I Keep Records
- Six years applies if you fail to report income exceeding 25% of the gross income shown on your return, which extends the IRS’s assessment window.23Internal Revenue Service. Topic No. 305, Recordkeeping
- Property records for any business asset should be kept until the limitations period runs on the tax year you sold or disposed of it. You need them to figure cost basis, depreciation, and gain or loss on sale.22Internal Revenue Service. How Long Should I Keep Records
Electronic storage is fine, as long as the files are legible, retrievable, and indexed so you can find a specific document. The system should also preserve an audit trail from general ledger entries back to source documents.24Internal 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. A dumping ground of unsorted scans won’t meet the standard.