How Maryland withholds on a bonus
Maryland's Employer Withholding Guide sets supplemental withholding at the state's top rate, 6.5% since the 2025 budget added the new brackets, plus the employee's county rate on the same bonus: 3.2% in Montgomery, Prince George's, Howard and Baltimore City, 2.25% at the low end. Combined state and county supplemental withholding is therefore 8.75% to 9.7%, among the highest in the country. On a $10,000 bonus the percentage method withholds $2,200 federal, $620 Social Security, $145 Medicare and $650 Maryland state, leaving $6,385 before the county line; a Montgomery County resident would see a further $320 withheld.
The 6.5% state rate applies on the return only to income above $1 million; a $60,000 earner's actual Maryland marginal rate is 4.75%, so the state over-withholds by about $175 on a $10,000 bonus. Under the aggregate method Maryland applies its brackets to the combined paycheck instead, withholding closer to 4.75% to 5%; the federal line rises to about $2,700.
What the withholding means for your Maryland return
A Maryland bonus over-withholds on both sides for most filers: 22% federal against a 12% to 22% marginal rate, and 6.5% state against 4.75%, so roughly $750 federal and $175 state return at filing on a $10,000 bonus for a $60,000 earner, while the county tax settles close to even. DC, Pennsylvania, Virginia and West Virginia residents who earn a bonus in Maryland are withheld for their home jurisdiction under reciprocity. The Maryland paycheck calculator shows the marginal rates for any salary.