Stoia

Personal finance glossary

Supplemental wages

Definition

Pay outside the regular paycheck: bonuses, commissions, severance, overtime, and similar. Employers commonly withhold federal tax on these at a flat percentage set by the IRS rather than your W-4 rate, which is why a bonus check looks unexpectedly small.

Why it matters

The heavy withholding is not an extra tax, just a different withholding method: your real tax is settled by your bracket at filing. Knowing that prevents both the bonus-day disappointment and bad decisions like refusing overtime.

Example

A $5,000 bonus arrives as roughly $3,300 after flat federal withholding plus payroll and state taxes. At filing, the bonus is taxed at the worker's actual marginal rate; if the flat withholding overshot it, the difference comes back in the refund.

Put it into practice

Related terms

This definition is educational, not financial, legal, or tax advice. U.S. rules and limits change; verify time-sensitive details with official sources. See our disclaimer.

See these terms in your own numbers

Stoia shows your net worth, budgets, and goals in one calm place, so the vocabulary becomes your dashboard. Launching in 2026.

Coming soon