Quarterly estimated taxes explained

W-2 employees have taxes automatically withheld from each paycheck, so they never think about when taxes are 'due.' Self-employed people don't have an employer withholding for them, but the IRS still wants its cut on a regular schedule. If you wait until April to pay, you owe a penalty for underpayment during the year.

The four deadlines

• Q1: April 15 — covers January through March earnings.
• Q2: June 15 — covers April and May.
• Q3: September 15 — covers June through August.
• Q4: January 15 of next year — covers September through December.

How much to pay

Two safe harbor rules let you avoid penalties. Pay either (1) 100% of last year's total tax liability split across the four quarters, or (2) 90% of this year's expected tax. The first is easier — just take last year's tax bill, divide by 4, and pay that amount each quarter. As long as you hit that number, no penalty applies even if you owe more in April.

Paying the IRS

Use EFTPS.gov (free, direct withdrawal), the IRS Direct Pay tool, or mail a check with Form 1040-ES. Your accountant can also set it up on your behalf. State estimated taxes are separate and have their own schedules — check your state's department of revenue.

A worked example: freelancer earning $90,000

Say you expect $90,000 of net self-employment profit this year, you are single, and you take the standard deduction. Self-employment tax runs about $12,700. Federal income tax on the remainder lands around $10,500 after the deduction for half your SE tax and the QBI deduction. Add a 5% state and your total bill is roughly $27,000 — meaning each quarterly payment should be about $6,750. Notice that is 30% of gross profit, which is exactly why the save-30%-of-every-payment habit exists: it back-solves to the right answer for most mid-income freelancers without a spreadsheet.

Now suppose last year your total tax bill was only $16,000 because you were part-time. The safe harbor rule says you can pay $4,000 per quarter — 100% of last year's liability — and owe zero penalty even though you will owe another $11,000 in April. That is not a trap; it is an interest-free loan from the IRS, as long as you actually park the difference in savings instead of spending it. High earners note: if your prior-year adjusted gross income exceeded $150,000, the safe harbor rises to 110% of last year's tax.

What the penalty actually costs

The underpayment penalty is not a flat fine — it is interest, computed quarterly at the federal short-term rate plus 3 percentage points (roughly 7-8% annualized in 2025-2026). Skip a $6,000 Q1 payment and pay it a year late, and the penalty is on the order of $450. Painful but not catastrophic, which is worth knowing: if a brutal cash-flow month forces you to choose between rent and the estimated payment, the IRS is effectively an 8% lender. Just do not make it a habit, and never confuse the penalty with the tax itself — the $6,000 is still due.

Setting up the system once

1. 1
   Open a dedicated tax savings account

   A separate high-yield savings account at your bank, labeled taxes. Money that lands here was never yours to spend, and at 4% interest it even earns while it waits.

2. 2
   Automate the 30% skim

   Every time a client payment clears, move 30% (35% in high-tax states like California or New York) to the tax account the same day. Some banks and tools like Found or Novo can do this automatically.

3. 3
   Put the four deadlines on your calendar

   April 15, June 15, September 15, January 15 — with reminders one week ahead. Note the uneven spacing: Q2 covers only two months, which surprises everyone once.

4. 4
   Create an EFTPS or IRS Direct Pay login now

   EFTPS enrollment takes about a week because the PIN arrives by mail. Do not discover this on June 14.

5. 5
   True-up each quarter

   Spend ten minutes comparing the tax account balance to profit year-to-date times your rate. Adjust the skim percentage if you are drifting.

Common mistakes that cost real money

• Forgetting that Q2 is only two months. April 15 to June 15 surprises everyone once — the payment is due before the money feels earned.
• Spending the tax account in a lean month and planning to catch up later. Later arrives with an 8% penalty clock running and a bigger hole.
• Ignoring state estimates entirely. States send their own penalty notices, and several assess them more aggressively than the IRS does.
• Basing payments on revenue instead of profit. Estimated tax is owed on net earnings after expenses — overpaying by taxing your gross is an interest-free loan to the government.
• Missing the January 15 payment because the holidays swallowed it. It covers four months of income and is usually the largest of the year.

The bottom line

Quarterly estimated taxes are only scary the first year. After that, the system runs itself: skim 30% of every deposit into a dedicated account the day it lands, pay the safe-harbor amount on the four deadlines, and true up in April with money that has been sitting there earning interest all along. The freelancers who get burned are almost never the ones who miscalculated by a few hundred dollars — they are the ones who treated gross deposits as spendable income for twelve months and met their real tax bill for the first time in April. One savings account and one recurring calendar reminder is the entire defense.

A final note on mid-year course corrections: estimated taxes do not have to be four equal payments. If your income arrives unevenly — a wedding photographer earning 70% of revenue between May and October, say — you can use the annualized income installment method on Form 2210 to match payments to when the money actually arrived. It is more arithmetic, but it stops the absurd situation of owing a large Q1 payment in a quarter where you earned almost nothing. Most tax software handles the annualization automatically if you feed it quarterly income figures, and for genuinely seasonal businesses it routinely eliminates penalties that the equal-payment schedule would have created.