Unpaid balance calculator

What your tax bill is really costing you

$

Since April 15, 2026

Failure-to-pay penalty $0
Interest accrued $0
Extra you owe on top of your balance, right now
$0
If it's still unpaid on
October 15, 2026
$0

Estimate only, based on the IRS's 0.5%-per-month failure-to-pay penalty (capped at 25%) and the current 7% annual underpayment interest rate, compounded daily. Your actual balance may differ — check IRS.gov/payments or your tax preparer for the exact figure.

Smart tax hacks with zero boring vibes 👇

We’re TaxStache — the loud, colourful antidote to boring tax talk. We cut through the jargon with a wink, a laugh, and the occasional bad moustache pun. We’re here to make you smarter, richer, and maybe even laugh along the way.