The Scenario
Elena’s bakery had its best year ever, and she expected a big tax refund. Instead she owes thousands in April, plus a penalty for underpaying throughout the year. Her reaction is the same one every new owner has: “Nobody told me about quarterly taxes.”
The IRS did tell her, in the fine print of her first 1040-ES voucher. But the real problem is that she treated taxes as an April event instead of a quarterly habit.
Who This Guide Is For
This is for self-employed people and small-business owners without payroll withholding: freelancers, gig workers, and LLC owners. If you have a full-time job that withholds taxes, your side income may still require estimated payments depending on how much you earn.
What to Look For
Quarterly taxes have three parts:
- The set-aside. A percentage of every deposit you move into a tax bucket.
- The calculation. Your projected income minus deductions, taxed at your rate.
- The payments. Four filings a year with the IRS and, in many states, your state tax agency.
How the System Works
The US tax system is pay-as-you-go. When you are an employee, your employer withholds taxes from each paycheck. When you are self-employed, no one withholds, so you are responsible for paying throughout the year.
The safe harbor: if you pay at least 90 percent of this year’s tax or 100 percent of last year’s tax (110 percent for higher incomes), you avoid the underpayment penalty. That rule gives new owners a practical baseline: pay roughly what you paid last year, adjusted for income changes.
Step-by-Step
1. Set your set-aside rate. Many owners start by moving 25 to 30 percent of every business deposit into a tax bucket. Adjust after your first full year when you know your real rate.
2. Calculate the payment. Use tax software or your accountant. If your income is stable, divide last year’s liability by four and pay that, which usually satisfies the safe harbor.
3. Pay on time. Pay electronically on the four due dates. Automatic scheduling turns this into a calendar event instead of a scramble.
4. Adjust mid-year. If income jumps or drops, recalculate at the September payment. One mid-year adjustment prevents most surprises.
5. Reconcile in April. File your return and compare total payments to your liability. Overpayment means a refund; underpayment means a bill. Either way, you now have a baseline for next year.
A Worked Example of the Set-Aside Math
Suppose your business nets $4,000 a month. You estimate your combined federal and state rate at roughly 30 percent, so you move $1,200 of every deposit into the tax bucket before spending a dime of the rest. Four times a year you pay the accumulated amount to the IRS and your state.
At the September payment, you notice income has climbed to $5,500 a month. You recalculate: 30 percent of $5,500 is $1,650, so the set-aside dollars grow with the income. If income had dropped, the same review would keep you from overpaying. That one mid-year review is what separates owners who owe a surprise in April from owners who already sent the money in four predictable installments.
Don’t Forget Your State
The federal estimate is only half the calendar. Most states with income tax require their own quarterly payments, often on the same schedule with their own voucher system. Look up your state’s rules when you set up the federal habit, and add both due dates to one calendar so the April surprise cannot hide in a second envelope you never opened. State rates vary widely, so your set-aside percentage should reflect your actual combined rate, not a guess.
What Not to Overpay For
Do not pay an accountant to file four simple estimated payments. Tax software handles this in minutes. Do not pay the IRS’s credit card convenience fee when a free bank transfer does the same job.
Also avoid the “I’ll deal with it in April” strategy. The penalty is small, but the April cash crunch is not.
What to Buy
For handling the calculation and filing yourself, TurboTax and TaxAct both guide self-employed filers through estimated taxes and year-end filing. H&R Block is a good option if you prefer in-person guidance at tax time. If you want the monthly math handled for you, Bench provides bookkeeping plus tax filing support for qualified plans.
Set the habit now: a percentage to savings, a calendar with four dates, and a software tool that makes each payment a ten-minute task.