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How Self-Employment Tax Works in Colorado (2026)
Self-employment tax is 15.3% — 12.4% Social Security plus 2.9% Medicare — applied to 92.35% of your net self-employment income, on top of federal and Colorado income tax. Half of the SE tax (7.65% equivalent) is an above-the-line deduction against your federal taxable income.
| Piece | Rate / rule |
|---|---|
| Net earnings subject to SE tax | 92.35% of net profit |
| Social Security portion | 12.4% (up to $184,500 of net earnings) |
| Medicare portion | 2.9% · +0.9% above $200,000 |
| Deductible half of SE tax | 50%, above-the-line on your federal return |
Estimated payments are due quarterly (roughly mid-April, mid-June, mid-September, and mid-January). The 20% Qualified Business Income deduction (§199A) is not modeled here — it depends on your income level and business type. If you also have W-2 wages, the Social Security cap is measured against your combined earnings, so this estimate runs high.
Colorado Self-Employment Tax by Income (2026)
Single filer, 1099 income is the only earnings for the year. The quarterly figure is an even 4-way split of the annual total.
| Net 1099 income | SE tax | Federal tax | Colorado tax | Quarterly payment |
|---|---|---|---|---|
| $20,000 | $2,826 | $249 | $109 | $796 |
| $40,000 | $5,652 | $2,281 | $927 | $2,215 |
| $60,000 | $8,478 | $4,511 | $1,745 | $3,684 |
| $80,000 | $11,304 | $7,527 | $2,563 | $5,348 |
| $100,000 | $14,130 | $11,616 | $3,381 | $7,282 |
Colorado Self-Employment Tax FAQ
How much is self-employment tax in Colorado?
15.3% federal SE tax on 92.35% of net profit (12.4% Social Security up to $184,500, 2.9% Medicare), plus Colorado's flat 4.40% income tax on net profit, plus federal income tax. Half the SE tax is a federal deduction.
Do 1099 workers pay quarterly taxes in Colorado?
Yes - federal estimated payments if you will owe $1,000 or more, and Colorado estimated payments once your unpaid state tax passes its threshold (check the Colorado Department of Revenue), on the mid-April / mid-June / mid-September / mid-January schedule.
Does Colorado allow the federal QBI deduction for the self-employed?
Colorado starts from federal taxable income, so the federal 20% QBI deduction does flow through to your Colorado return. This calculator does not model QBI because it phases out by income and business type.
Methodology & Source
Colorado state tax figures sourced from Colorado Department of Revenue (https://tax.colorado.gov/), citing Colo. Const. art. X (flat rate mandate) — 4.4% per Proposition 121 (2022). Federal brackets, standard deductions (single/MFJ/HoH), and FICA constants sourced from the IRS (Revenue Procedure 2025-32; married-filing-jointly Additional Medicare threshold of $250,000 is a separate, unindexed statutory figure). Colorado's married-filing-jointly and head-of-household figures are not yet independently verified and currently fall back to single-filer brackets — see the caveat in the formula section above.
Self-employment tax uses the statutory 15.3% rate (12.4% Social Security + 2.9% Medicare) on 92.35% of net self-employment income, with half of the SE tax deducted from federal taxable income above-the-line — per IRS Schedule SE (Form 1040) instructions, IRC §1401 and §164(f), 2026 edition. The 20% Qualified Business Income deduction (IRC §199A) is not modeled — it phases out by income and business type and is too state/entity-dependent to compute generically. This assumes the self-employment income is your only earnings for the year; if you also have W-2 wages, the Social Security wage-base cap and Additional Medicare threshold are actually based on your combined earnings, so this will overstate SE tax if you have significant wage income too.
This is an estimate based on standard single-filer federal, FICA, and CO state calculations. Actual withholding may differ based on your W-4 elections, pre-tax deductions, and other factors. Colorado starts from federal taxable income; this estimate applies the federal standard deduction as the base. Colorado's TABOR mechanism can temporarily lower the effective rate in high-revenue years, not modeled here.
Guideline version: 2026-CO-v1 · Effective: 2022-01-01 · Last verified: 2026-07-26