Calculator
1099 quarterly tax estimator
Enter your annual 1099 income, business expenses, and a few personal details. The calculator estimates federal income tax, self-employment tax, and quarterly payment amounts using current tax brackets.
Your numbers
Estimated taxes
Enter your numbers and click Calculate.
What does the calculator actually do?
The calculator runs a simplified version of the federal calculation that determines your total federal tax liability for the year, then divides by four for quarterly payments.
- Net business income. Revenue minus expenses equals net Schedule C income.
- Self-employment tax. Net income times 92.35 percent equals SE tax base. Then 15.3 percent on the first $176,100 (2025 wage base) and 2.9 percent above. Half of SE tax is deductible.
- Adjusted gross income. Net business income plus other income minus half SE tax equals AGI.
- QBI deduction. 20 percent of net business income (subject to income-threshold limits not modeled here for simplicity).
- Taxable income. AGI minus standard deduction minus QBI deduction equals taxable income.
- Federal income tax. Apply 2025 federal brackets for filing status to taxable income.
- Total federal tax. Federal income tax plus full SE tax.
- Quarterly payment. Total federal tax divided by 4.
Standard deductions used: $15,000 single, $30,000 MFJ, $22,500 HOH (2025 figures). Federal brackets used are the 2025 published brackets. The calculator does not handle: state income tax, additional Medicare tax for high earners, Net Investment Income Tax, alternative minimum tax, withholding offset from W-2 jobs, or itemized deductions. Use it as a directional planning tool.
1099 calculator FAQs
Why is the self-employment tax so high?
Self-employment tax is the contractor equivalent of FICA (Social Security and Medicare) taxes that W-2 employees split with their employer. As a self-employed person, you pay both halves: 12.4 percent Social Security on the first $176,100 (2025 wage base) and 2.9 percent Medicare with no cap, totaling 15.3 percent on the first chunk. Half is deductible on the federal income tax calculation, but the cash outlay is still 15.3 percent of net earnings.
What if I also have a W-2 job during the year?
Add your W-2 wages (after pre-tax retirement contributions) to the "Other taxable income" field. The calculator will tax the combined income. If your W-2 withholding is enough to cover both your W-2 portion and the additional 1099 federal income tax, you may not owe quarterly estimates. We work through that on intake. The calculator estimate is a worst-case (no W-2 withholding offset).
Why is the QBI deduction worth so much?
The qualified business income (QBI) deduction allows up to 20 percent of net business income to be deducted from taxable income, lowering the federal income tax (not SE tax). For a sole proprietor with $50k of net business income, that's a $10k deduction worth roughly $1,200-$2,400 in tax savings depending on bracket. Income thresholds and "specified service trade or business" classifications can limit or disqualify the deduction; this calculator does not model those limits.
Are the brackets and standard deduction current?
The calculator uses 2025 published federal brackets and standard deduction amounts. These are adjusted annually for inflation. We update the calculator as new figures are released. The current calculation should be reasonably accurate for tax year 2025 planning. For tax year 2026 and later, results will need adjustment for new brackets and standard deduction amounts.
Should I trust this for actual quarterly payments?
Use it as a planning estimate, not a filing calculation. Real quarterly calculations need to factor in: state income tax (varies dramatically by state), W-2 withholding from any employee jobs, additional Medicare tax for higher earners, Net Investment Income Tax, alternative minimum tax (rare but possible), full itemized deductions where applicable, and the safe-harbor calculation based on prior year. The year round advisory engagement handles all of that.
Want this calculation done correctly?
Year round advisory engagements include real quarterly calculations with full state-specific detail. Memberships start at $79 per month.