Free tool
RSU withholding calculator
Put in what's vesting and your 2026 bracket. You'll see how much federal tax gets held back at vest, how much you'd actually owe, and the gap you'd pay when you file.
Calculator
Will you owe more on your next vest?
Most companies hold back a flat 22% for federal tax when RSUs vest. If you're in a higher bracket, you owe the rest when you file.
About 13% of the vest.
This only covers federal income tax. It leaves out state tax, Social Security (6.2% up to $184,500 of wages), Medicare (1.45%, plus 0.9% over $200,000), and the chance the vest bumps you into a higher bracket. Some employers withhold differently. It's a rough estimate, not tax advice.
Go over your vests with meHow the math works
RSUs count as supplemental wages. Under IRS Publication 15, employers can withhold a flat 22% on the first $1 million of supplemental pay in a year, and they have to withhold 37% on anything past $1 million.
The calculator takes the vest value, applies 22% up to whatever is left of that $1 million (after the RSU and bonus pay you've already had this year) and 37% on the rest. Then it compares that to the vest value times the bracket you pick. The difference is roughly what you'd still owe, or get back, when you file.
Example: a $86,412 vest at a 35% bracket is about $30,244 of federal tax. Withholding at 22% is about $19,011, so you'd be short about $11,234.
What it leaves out
State tax, Social Security and Medicare, the chance the vest pushes part of your income into a higher bracket, and employers that withhold at your W-4 rate instead of the flat 22%. It's a quick estimate, not a tax return. The brackets and limits behind it are on the 2026 numbers page, each with its source.