Tax calculators
Tax rules change every year and hide their exceptions in the footnotes. Each of these shows the tax year it uses, where the numbers come from, and what it doesn't cover.
Estimated Tax Safe Harbor
The least you can pay in estimated taxes and still owe no underpayment penalty — which rule you're under, what's left after withholding, and what to send each quarter.
Open calculatorQuarterly Estimated Tax
Check your estimated payments quarter by quarter, the way Form 2210 does: what was due by each date, where you came up short, and what it takes to catch up.
Open calculatorSelf-Employment Tax
The Social Security and Medicare tax you pay as your own boss, figured line by line like Schedule SE — including a W-2 job's effect on the wage base, the Additional Medicare Tax, and how much to set aside.
Open calculatorSection 179
How much of a new asset you can write off this year under Section 179 — the dollar limit, the phase-out, the business income limit, the carryforward, and the basis that's left for bonus depreciation and MACRS.
Open calculatorDepreciation Recapture
Sold equipment or a building you depreciated? Split the gain the way Form 4797 does — recapture taxed as ordinary income, unrecaptured §1250 gain at up to 25%, and the rest as Section 1231 gain or loss.
Open calculatorInstallment Sale
Selling property and letting the buyer pay over time? Spread the gain over the years you're paid, the way Form 6252 does — with recapture up front, the interest, and a year-by-year schedule.
Open calculator