Concept site Greenbar CPAs is a fictional accounting firm, designed and built by Patrick Bushe to show what I make for accounting firms. Fictional, by Patrick Bushe

Estimated tax calculator

Three numbers in, four payments out. Uses the safe-harbor rule, so paying these on time means no underpayment penalty.

Sample tool A sketch of the federal safe-harbor math, not tax advice. Dates move to the next weekday when they land on a weekend; holidays aren’t counted here.

Next payment
Form 1040-ES
    Total

    Questions owners ask

    Do I have to pay estimated taxes?

    Usually, if you expect to owe $1,000 or more when you file, after withholding and credits. That covers most self-employed people and owners who take profit out of an LLC or S corp.

    Why pay last year’s tax instead of this year’s?

    It’s the safe harbor. Pay 100% of last year’s total tax in four equal parts (110% if your adjusted gross income was over $150,000) and there’s no underpayment penalty, even if you owe more in April.

    My income is lumpy. Do I have to pay equal amounts?

    No. The annualized income method lets you pay less in slow quarters and more in busy ones. It takes more math, which is part of what the planning add-on is for.

    What about California?

    California has its own schedule: 30% in April, 40% in June, nothing in September and 30% in January. We figure both and send you one reminder with the two amounts.

    Hands at a laptop next to a calculator, a notebook and a coffee, seen from above

    Rather we just send you the number?

    On the Books + Tax plan we figure your estimates from this year’s actual books, federal and California, and email the amounts two weeks before each date.