Quarterly Estimated Taxes

If no one withholds tax from your income, the IRS expects four payments a year — on a schedule that is not actually quarterly. Who must pay, the safe-harbor rules that end the guesswork, and a system that makes the deadlines boring.

The U.S. tax system is pay-as-you-go. Employees satisfy this automatically through withholding; everyone else — freelancers, landlords, investors with meaningful untaxed income — is expected to send money in as the year progresses. Miss the schedule badly enough and an underpayment penalty accrues like interest, even if you pay in full by April.

The un-quarterly quarters

The four deadlines fall in April, June, September, and January — covering periods of three, two, three, and four months. The June date in particular ambushes new freelancers, arriving two months after the first. Put all four on a calendar with reminders a week early; this one act removes most of the stress.

Safe harbors: the rules that end the guesswork

You do not need to predict your income perfectly. Penalties generally do not apply if your payments through the year reach any one of these marks:

90% of this year's actual tax — accurate but requires forecasting;
100% of last year's tax (110% for higher incomes) — the workhorse rule, because last year's number is printed on last year's return;
or you owe less than $1,000 after withholding.

The prior-year harbor turns an estimation problem into a division problem: take last year's total tax, divide by four, pay on schedule. If this year turns out better, you settle the difference in April — without penalty.

A system that runs itself

Separate the money on arrival. A fixed slice of every payment received goes to a tax-only savings account the day it lands. The estimate check is then a transfer, not a scramble.
Use withholding if you have any. Withholding is treated as spread evenly across the year no matter when it happens — a W-2 job (yours or a spouse's) can cover freelance income through a W-4 adjustment as late as December, a flexibility estimated payments do not have.
Recalibrate mid-year. One check-in around the June or September date, comparing actual income against the assumption, prevents both underpayment and a needless interest-free loan.

Size the underlying number with the self-employment tax calculator and the federal income tax calculator — together they produce the annual figure the four payments must add up to.

Quarterly Estimated Taxes: Who Owes Them and How to Stop Fearing Them

The un-quarterly quarters

Safe harbors: the rules that end the guesswork

A system that runs itself

Run your own numbers

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