The biggest update since launch. PAY THE LEAST YOU LEGALLY CAN • What to set aside from each payment — the real tax it causes, not a flat percentage. Past the Social Security cap the rate drops sharply • How much you can put into a SEP-IRA or solo 401(k), worked out from your own profit, and what each contribution takes off this year's tax. A solo 401(k) usually allows far more than a SEP • Your household: a spouse's salary, withholding, a retirement contribution — each moves what you owe by thousands KNOW WHAT APRIL HOLDS • Safe harbor stops the penalty, not the bill. See yours building up on income you have already been paid — a running total, never a forecast • We now tell you when you are under the $1,000 federal threshold and do not have to pay estimated tax at all SEE THE WORK • Every line of the calculation, traced back to the 2026 IRS tables • Your state's own rules in your own dollars — California asks 30/40/0/30, not four equal payments • Income by client: who paid what, and what share of your year each is STAY ON TOP OF IT • A set-aside tracker: what you have put away against what the quarter needs, and one tap to add to it when you log income • A home screen widget with your number and the countdown • Pay on IRS.gov straight from the app when the quarter is due FOR YOUR ACCOUNTANT • A year-end PDF: income by client, every payment with its confirmation number, estimated vs actual, Schedule C basis • Record the confirmation number when you mark a quarter paid, so you have proof if the IRS ever asks Deadlines now follow the IRS weekend and holiday rule for every year, not just the ones we had listed.