Why 30% is the default set-aside
A freelance editor's tax bill stacks three layers. First, self-employment tax: a flat 15.3% on net profit, covering Social Security and Medicare, owed from the first real dollar of profit. Second, federal income tax at your bracket, which for a full-time editor commonly lands in the low-to-mid teens as an effective rate after the standard deduction. Third, state income tax, anywhere from zero in states like Texas and Florida to a meaningful slice in California or New York.
Add those together and 30% of profit is the number that keeps most editors safe. It is deliberately a little conservative for modest incomes; the reward is that tax deadlines become non-events and any leftover becomes a bonus. Editors earning six figures, or living in high-tax states, should lean toward 35%. A part-timer whose editing profit sits on top of a W-2 job should remember the profit stacks on top of salary and can be taxed at a higher marginal rate than expected, so 30% remains a sound floor even for side income.
Save on profit, not on gross deposits
The percentage applies to profit, not to every dollar clients send. If you bill $8,000 in a month and spend $1,500 on software subscriptions, plugins, stock assets, and gear, your taxable profit is $6,500, and the set-aside is about $1,950, not $2,400. This is why tracking write-offs all year is not bookkeeping busywork: every logged expense directly shrinks the amount you need to save.
The mechanics matter as much as the math. Open a separate savings account used only for taxes. Each time a client payment lands, move the percentage over immediately, the same day. The money you can spend is what remains. Editors who skim first never face a five-figure surprise in April; editors who plan to catch up later almost always do.
Sending it in with Form 1040-ES
Saving the money is half the job; the IRS also wants it during the year. Quarterly estimated payments are due around April 15, June 15, September 15, and January 15, paid with Form 1040-ES vouchers or, more easily, through the IRS online payment system. Skip them and the IRS charges an underpayment penalty that works like interest, even if you pay in full at filing time.
There is a shortcut that removes the guesswork: the safe harbor. Pay in at least 100% of last year's total tax (110% if your adjusted gross income was above $150,000), spread across the four dates, and you are penalty-proof no matter how much you earn this year. In a growing year that means your quarterly payments are based on the smaller prior year, and you settle the difference at filing, with the cash already sitting in your tax account because you saved 30% all along.