What is Form 8959?
Form 8959 calculates the 0.9% Additional Medicare Tax on combined W-2 Medicare wages and self-employment income exceeding the filing status threshold: $200,000 for Single, $250,000 for MFJ, or $125,000 for MFS. The threshold is shared between wages and SE income — wages are applied first, and any remaining threshold applies to SE income.
SupportedKey Lines
| Line | Description | Destination |
|---|---|---|
| Line 7 | Additional Medicare Tax on wages | 0.9% on wages above threshold |
| Line 13 | Additional Medicare Tax on SE income | 0.9% on SE income above remaining threshold |
| Line 18 | Total Additional Medicare Tax | Schedule 2 Line 11 |
| Line 19 | Medicare tax withheld (W-2 Box 6) | Offset against liability |
How PaisaTax Handles It
- Computed automatically when combined Medicare wages and SE income exceed the threshold
- W-2 Box 5 provides Medicare wages; Schedule SE Line 4a provides SE income
- Threshold allocation applies wages first, remaining threshold reduces SE income subject to tax
- Withholding credit from W-2 Box 6 offsets the total Additional Medicare Tax liability
Common Situations
- High-wage employee: Single filer with $250,000 W-2 wages — 0.9% on $50,000 excess = $450.
- Wages plus SE income: $180,000 wages + $50,000 SE income. Wages use $180K of threshold, SE income taxed on $30,000 (remaining $20K threshold absorbs first $20K of SE).
- MFJ combined income: Both spouses' wages are combined against the $250,000 MFJ threshold.