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Taxes • 2 min read

Self-Employed Tax & Quarterly Estimator

Estimate federal self-employment tax (15.3%), income tax brackets, and recommended quarterly set-aside amounts.

By Enow A. Jovial • Published 2026-08-22

Tax Estimator: Quarterly Estimated Tax Planner for the Self-Employed

This estimator converts a self-employed or single-member LLC owner's net profit into a quarterly estimated tax figure. It is a planning estimate using simplified US federal brackets — not tax advice. Consult a licensed tax professional before filing or paying. The calculation runs in four steps:

```

1. SE Tax Base = Net Profit × 92.35%

2. SE Tax = SE Tax Base × 15.3%

3. Taxable Income = Net Profit − (SE Tax ÷ 2) − Standard Deduction

4. Total Tax = SE Tax + Income Tax on Taxable Income; Quarterly = Total Tax ÷ 4

```

What each step means. Self-employment (SE) tax covers Social Security and Medicare. Because employers normally pay half, you are taxed on only 92.35% of net profit, and you may deduct half of the SE tax before computing income tax. The standard deduction and bracket thresholds below are illustrative figures in the range of recent single-filer amounts; always substitute the current IRS-published values for your filing year and status.

Worked example: $90,000 net profit, single filer, illustrative standard deduction of $15,750.

Step 1: $90,000 × 0.9235 = $83,115.00 SE tax base

Step 2: $83,115.00 × 0.153 = $12,716.60 SE tax

Step 3: $90,000 − $6,358.30 (half of SE tax) − $15,750 = $67,891.70 taxable income

Step 4, income tax by bracket: 10% × $11,925 = $1,192.50; 12% × ($48,475 − $11,925) = $4,386.00; 22% × ($67,891.70 − $48,475) = $4,271.67. Income tax total = $9,850.17

Total estimated tax: $12,716.60 + $9,850.17 = $22,566.77, or $5,641.69 per quarter — an effective rate of roughly 25.1% of net profit.

Limitations — when not to rely on this. The estimator excludes state and local taxes, the qualified business income (QBI) deduction, retirement-plan contributions, credits, and income above the Social Security wage base, where the 15.3% rate changes. S-corporation owners are taxed differently. Material income swings during the year also make even quarterly splits inaccurate.

> [!TIP]

> Base each quarterly payment on year-to-date profit rather than last year's income if your revenue is growing; underpayment penalties are calculated per quarter, and a strong Q4 does not erase a short Q1 payment.