Business expenses for 1099 workers
Learn how ordinary business expenses reduce net self-employment income and what records to keep.
What counts as a business expense
A business expense is generally a cost connected to earning self-employment income. For calculator planning, expenses reduce gross receipts to net self-employment income before the self-employment tax worksheet is applied.
Do not enter personal spending simply because it happened while working. The estimate is only useful when the expense amount is tied to documented business activity.
Mileage, home office, and software
Mileage, home office, software, supplies, payment processing fees, platform fees, professional services, and insurance can be common categories, depending on the work. Some expenses have special rules or recordkeeping requirements.
For vehicle costs, you may need to choose between the standard mileage rate and actual expense method. The calculator accepts a total annual expense number and leaves method selection to your tax records or professional review.
How expenses change quarterly payments
Every additional dollar of allowed expense can reduce income tax and may also reduce self-employment tax because the SE calculation starts with net earnings. That is why the result panel includes a $1,000 expense impact line.
The impact is an estimate, not a promise. Bracket thresholds, credits, state rules, and the Social Security wage base can change the marginal effect.
The guide explains the rule. The calculator shows how it changes your next quarterly payment.
Open the calculator