The 15.3% federal tax (12.4% Social Security + 2.9% Medicare) on net earnings from self-employment. The Social Security portion applies only up to the SSA wage base — $184,500 for 2026 — while the 2.9% Medicare portion has no cap. Gig workers pay both halves themselves where W-2 employees split it with an employer; half of the SE tax is then deductible above the line on the 1040.
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