The IRS wants its money four times a year, not once

If you’ve only ever had a W-2 job, tax season is a once-a-year thing. Drive for a living and it’s a four-times-a-year thing, and nobody hands you the schedule.

Why quarterly, specifically

A W-2 employer withholds tax from every paycheck and sends it to the IRS on your behalf, all year, automatically. As a 1099 driver, nobody’s doing that for you — which means the IRS expects you to send in your own estimated payments as you earn, not in one lump sum the following April.

The due dates land roughly in the middle of April, June, September, and the following January — four payments covering the prior income period, not neat calendar quarters. Miss the pattern and you’re not just late once, you can be late four separate times.

What actually happens if you skip it

Nothing dramatic happens the day you miss a quarterly payment — no letter shows up immediately. What happens is quieter: the IRS calculates an underpayment penalty based on how much you owed each quarter and how late you paid it, then adds that penalty to your bill when you file. It’s interest-like, not a flat fine, and it compounds the longer you wait to pay any given quarter.

The safe-harbor number that makes this simple

You don’t have to predict your income perfectly to avoid the penalty. The IRS gives you a safe-harbor rule: pay in, across the year, at least the smaller of two numbers — a percentage of what you expect to owe this year, or a percentage of what you actually owed last year. Hit either threshold through your quarterly payments and the underpayment penalty doesn’t apply, even if your final number ends up higher.

That second option — basing this year’s payments on last year’s bill — is the one most drivers should actually use. It doesn’t require guessing this year’s income at all, just knowing last year’s number and dividing it by four.

The exact rule: your withholding and estimated payments together need to add up to at least the smaller of 90% of what you’ll owe this year, or 100% of what you owed last year. If your prior year’s adjusted gross income was over $150,000 ($75,000 if married filing separately), that second number moves up to 110%. Either safe-harbor threshold only applies if last year’s return covered a full 12 months.

For 2026, the four due dates are April 15, June 15, September 15, and January 15, 2027 — each covering the income earned in the quarter before it. (If any of those lands on a weekend or legal holiday, it pushes to the next business day.) These are set by the IRS and don’t change year to year except for the calendar shifting, so it’s worth a quick check at irs.gov/faqs/estimated-tax before each payment if you want to confirm nothing’s moved.