How does DeskOps work out what I owe in tax?

It starts with your gross receipts for the period, subtracts the expenses you have tracked over the same dates, and runs what is left through the current year's tax constants for your entity type, your state and your filing status: federal income tax by bracket, self-employment tax (not applied to an S-corp), the QBI deduction under §199A where it applies, and your state's income tax. Meals are the one book-to-tax adjustment it makes, at fifty percent. The result is shown three ways — what the current quarter looks like, the annual estimate, and a weekly amount to set aside — and every screen says the same thing: an estimate, not advice; confirm with a licensed CPA before you file. DeskOps files nothing.