Montana Bonus Tax Calculator (2026)
Montana withholds 5% state income tax on bonuses, on top of the federal 22% and 7.65% FICA.
Montana rules for bonuses
Optional flat supplemental rate. Published rates: 5% for supplemental wages paid separately (commissions, bonuses, overtime).
- Alternatives: add to current or last preceding period's regular wages
- 2026 formula 4.7% / 5.65% (HB 337)
If supplemental wages are paid separately (for example, a holiday bonus), you can choose to withhold the tax by using one of the following ways: ... a flat 5 percent of the supplemental wage.
Local taxes: None
Take-home bonus by amount
| Bonus | Federal (22%) | FICA | State | Take-home |
|---|---|---|---|---|
| $1,000 | $220 | $77 | $50 | $654 |
| $2,500 | $550 | $191 | $125 | $1,634 |
| $5,000 | $1,100 | $383 | $250 | $3,268 |
| $10,000 | $2,200 | $765 | $500 | $6,535 |
| $20,000 | $4,400 | $1,530 | $1,000 | $13,070 |
| $50,000 | $11,000 | $3,825 | $2,500 | $32,675 |
Sources
Frequently asked questions
What is the bonus tax rate in Montana?
Montana withholds 5% on bonuses when the employer chooses the flat supplemental rate, on top of the federal 22% and 7.65% FICA.
How much of a $10,000 bonus do I keep in Montana?
About $6,535 for a single filer earning $85,000: $2,200 federal, $765 Social Security and Medicare and $500 state.
Will I get some of the bonus tax back?
Possibly. The 22% federal rate is only withholding. At tax time your bonus is taxed at your bracket (22% at this salary), and Montana's flat supplemental rate can also differ from your actual state rate.