Quarterly Estimated Tax CalculatorFigure out what you owe the IRS, and when.

Why the IRS wants four checks a year

Let's lay it out on the table, man. The US tax system is pay-as-you-go. W-2 employees pay every two weeks because their boss withholds the tax and wires it to the IRS. Freelancers do not have a boss doing that, so the IRS requires the freelancer to mail in four checks a year instead. Skip a check and a little letter arrives in April with a penalty attached.

This is the Quarterly Tax Absurd. The grumpy little bureaucrat who waits in the mailroom with an IRS form in one hand and a calculator with no instructions in the other. He does not tell you the safe harbor rule. He does not tell you about Form 2210. He just mails you a penalty notice the following April and smirks when you open the envelope.

Most first-time freelancers do not even know the rule exists. They file in April, find out they owe $15,000, cut the check, and three weeks later get a second letter adding a $300 underpayment penalty. Nobody warned them. The IRS assumes you read Publication 505 cover to cover.

FigureNerd does not assume that. The calculator up top figures your tax, figures your safe harbor, and gives you four payments with the actual 2026 due dates. Pay on the dates, penalty avoided.

The 4 dates you cannot miss

The IRS breaks the year into four periods, but they are not calendar quarters. Q1 covers January through March and is due April 15. Q2 covers April and May only (two months) and is due June 15. Q3 covers June, July, and August, due September 15. Q4 covers September through December, due January 15 of the following year. The uneven month counts are why people get confused.

If a due date falls on a Saturday, Sunday, or federal holiday, the deadline shifts to the next business day. April 15, 2026 lands on a Wednesday, so the Q1 due date is the standard date with no shift.

Most states that collect income tax follow the same four dates for state estimates. A handful, Iowa and Delaware among them, use a slightly different schedule. Check your state's department of revenue site before writing state checks.

Safe harbor: the two paths to zero penalty

Here is the piece of the tax code that actually protects you, and almost nobody learns about it until after they have already been penalized. Safe harbor. It means the IRS will not charge an underpayment penalty, period, if your withholding plus estimated payments reaches one of two thresholds.

Path one: pay at least 90 percent of your current year's total tax. Problem with this path: you do not know your current year's total tax until January. You are guessing all year. If you guess too low, the penalty hits.

Path two: pay at least 100 percent of last year's total tax (110 percent if your prior year AGI was over $150,000, or $75,000 if married filing separately). This path is the one most freelancers use, because last year's total tax is a known, fixed number sitting on line 24 of your prior 1040. Pay to that number in four equal installments and the safe harbor locks in, full stop, even if your current year income triples.

The calculator above shows both paths. The "safe harbor" line tells you the smaller of the two thresholds, because that is the number the IRS actually enforces. You can pay to either, not both.

What happens if you underpay

If your total withholding plus estimates falls short of both safe harbor thresholds, the IRS charges an underpayment penalty. The penalty is calculated on Form 2210 and varies by how short you were and when the shortfall occurred during the year. Missing the Q1 payment costs more than missing Q4, because the IRS calculates interest from the due date to the payment date.

The rate floats with the short-term applicable federal rate (AFR) plus 3 percent, which has been running 7 to 8 percent annualized in recent years. For a typical freelancer who underpaid by $5,000 for a full year, the penalty runs roughly $200 to $400. For larger underpayments or longer stretches, it scales proportionally.

The IRS sends the penalty notice automatically, usually about three weeks after you file your return and settle up. You can dispute it with reasonable-cause arguments (retirement, disability, disaster, first-year filer), but default outcome is you pay.

There is also a small-balance exemption. If your total tax after withholding and refundable credits is under $1,000 for the year, no penalty regardless of estimates. And first-year filers (people with no prior-year tax return) get a pass on the 100 percent prior-year safe harbor path, because there is no prior year to reference.

Companion story: How one freelancer missed 3 quarters and what happened

Reddit says

If you spend 20 minutes on r/tax, r/freelance, or r/personalfinance, the same three questions repeat every quarter. Here is what the community tends to converge on, paraphrased for the FigureNerd voice.

Methodology: how the calculator actually figures this

We show our math so you can trust the number. Here is the order of operations the calculator runs, using 2026 rates and thresholds.

1. Self-employment tax. SE base = net SE income × 0.9235. Social Security portion = 12.4 percent on SE base up to the 2026 wage base of $184,500. Medicare = 2.9 percent on all of SE base. Additional Medicare = 0.9 percent on wages plus SE earnings above $200,000 (single) or $250,000 (MFJ). Total SE tax is the sum.
2. Adjusted gross income. AGI = SE income + W-2 income + other income − (1/2 × SE tax) − pre-tax retirement contribution.
3. Taxable income. Taxable income = AGI − standard deduction.
4. Federal income tax. Run taxable income through the 2026 progressive brackets for your filing status. Single brackets for 2026: 10% to $12,400, 12% to $50,400, 22% to $105,700, 24% to $201,775, 32% to $256,225, 35% to $640,600, 37% above. MFJ brackets double most thresholds.
5. Total federal tax. Federal income tax + SE tax.
6. Remaining federal owed. Total federal tax − W-2 withholding − YTD estimates already paid.
7. Safe harbor threshold. The smaller of (90% × current year total tax) or (100% × prior year tax, or 110% if prior year AGI exceeded $150,000). Displayed alongside the "you need to pay" number.
8. State tax. We apply your state's top marginal rate to taxable income as a planning estimate. Real state tax depends on bracket; the directional estimate is close for most freelancers.
9. Quarterly payment. Remaining federal owed + state tax, divided by 4. Paid April 15, June 15, September 15, January 15.

Where we simplify: we do not run the annualized-income method (Form 2210 Part III), which can lower penalties for people with lumpy income. We do not model Qualified Business Income (QBI) deduction, which can reduce taxable income 20 percent for most pass-through income. We do not model child tax credit, EITC, or other refundable credits. We do not model additional Medicare tax on investment income (NIIT, 3.8 percent above MAGI thresholds). If your situation is complex, run the numbers here as a sanity check, then hand the actual return to a CPA.

Worked example: the calculator's own default numbers

Run the page's defaults exactly as they load: $85,000 expected net self-employment income, single filer, Florida (no state income tax), $6,000 in pre-tax retirement contributions, $14,000 in last year's total federal tax, nothing paid yet this year.

Self-employment tax comes to $12,010 (15.3 percent on the SE-adjusted base up to the Social Security wage base). After subtracting half of that SE tax and the $6,000 retirement contribution from total income, then applying the 2026 single-filer brackets to the resulting taxable income, federal income tax comes to $7,229. Total federal tax: $19,239. With nothing already paid, the full $19,239 is still owed for the year.

The safe-harbor comparison picks the smaller of two numbers: 90 percent of this year's projected federal tax ($17,315) or 100 percent of last year's tax ($14,000, since this year's total income doesn't cross the $150,000 high-earner threshold). $14,000 wins, so the calculator's own guidance is to pay at least $14,000 across the year, or $3,500 per quarter, to lock in safe harbor, even though the actual 2026 liability projects higher at $19,239. Paying only to the safe-harbor floor avoids the penalty but leaves a balance due in April; the calculator's headline number ($4,810 per quarter) targets the full year's liability instead, so you owe nothing extra at filing time.

When the safe-harbor "high earner" rule can use the wrong year's income

The 110 percent high-earner safe harbor rule is supposed to trigger based on your prior year's adjusted gross income exceeding $150,000. This calculator does not ask for your prior-year AGI directly, only your prior-year total tax dollar amount, so it substitutes your current year's total income as a stand-in for whether the 110 percent rule applies, a heuristic the page's own code comments disclose openly.

That substitution can misfire in exactly the situation quarterly-tax planning matters most: a year where your income changed a lot. Enter $200,000 in current-year self-employment income with an $8,000 prior-year tax bill (implying a much smaller prior-year income), and the calculator applies the 110 percent multiplier, targeting an $8,800 safe-harbor floor. The same $8,000 prior-year tax entered with a current income under $150,000 produces a $8,000 safe-harbor floor at the standard 100 percent rate. Same prior-year number, different verdict, purely because of what current-year income happens to be.

If your income jumped or dropped significantly from last year to this year, don't trust the calculator's 110-percent-or-100-percent labeling at face value. Pull your actual prior-year Form 1040 line for AGI and compare it to $150,000 yourself; the dollar target the calculator computes from your entered prior-year tax figure is still correct arithmetic, but which multiplier it applies can be wrong when income is not steady year over year.

Mistakes to avoid with this calculator

• Paying only the safe-harbor amount when you can afford more. Safe harbor avoids the penalty, not the bill. On the default scenario, safe harbor is $14,000 but the actual projected liability is $19,239; paying only to safe harbor still leaves a $5,239 balance due at filing, without the underpayment penalty on it but with the full cash-flow hit in April.
• Trusting the 110% vs 100% label when your income changed year over year. As shown above, the calculator infers the high-earner rule from current-year income, not actual prior-year AGI. Verify against your real prior-year return if your income moved significantly.
• Forgetting the state tax line is a top-marginal-rate estimate, not your actual state liability. Most states have their own bracket structure; the flat top-rate estimate here is a planning number, not a filing-ready figure.
• Leaving retirement_contrib and std_deduction at their defaults when yours differ. Both directly reduce taxable income and change every downstream number. Confirm your actual pre-tax retirement contribution and correct standard (or itemized) deduction before trusting the total.
• Ignoring the S-Corp hint threshold is about this year's SE tax, not overall tax strategy. The hint appears once SE tax alone clears $3,000, a low bar reached by most steady freelance incomes; it is a nudge to go run the dedicated S-Corp calculator, not a verdict that an S-Corp election is worth it at your income.

When you should skip this calculator and hire a CPA

There is a point where a generic calculator, even a good one, is not enough. If any of these describes you, the cost of a CPA (typically $400 to $1,500 per return) pays for itself in avoided penalties and surfaced deductions.

• You have an S-corp election and need reasonable-salary + distribution planning
• You own rental real estate or have passive loss carryovers
• You have significant investment income triggering NIIT
• You have multi-state income from remote work or a spouse in a different state
• You had a major life event (marriage, divorce, dependent change, inheritance)
• You are newly self-employed and unsure which expenses are deductible
• Your combined income with a working spouse crosses higher-earner thresholds (200K+)

For simple freelance or 1099 income with one state and no weirdness, the calculator above is usually within a few hundred dollars of what a CPA's projection would be.

FAQ: quarterly estimated tax calculator

Do I have to pay quarterly estimated taxes?

If you expect to owe at least $1,000 in federal tax for the year after subtracting withholding and refundable credits, the IRS generally expects you to pay estimated tax in four quarterly installments. Freelancers, 1099 contractors, sole proprietors, single-member LLC owners, S-corp owners with under-withheld distributions, landlords, and anyone with significant investment income all typically fall into this rule. If you have a W-2 job with enough withholding to cover your tax bill, you can often skip quarterly entirely.

When are the quarterly tax due dates for 2026?

The four federal estimated tax due dates for the 2026 tax year are April 15 2026 (Q1), June 15 2026 (Q2), September 15 2026 (Q3), and January 15 2027 (Q4). The Q4 payment covers income earned between September and December 2026. If a due date falls on a weekend or holiday, the deadline shifts to the next business day. Most states follow the same schedule for state estimates.

What is the safe harbor rule?

The safe harbor rule lets you avoid the underpayment penalty if your total withholding plus estimated payments equals at least the smaller of 90 percent of your current year tax liability or 100 percent of last year's total tax. For higher earners with adjusted gross income over $150,000 ($75,000 if married filing separately), the prior-year threshold jumps to 110 percent. Paying to the prior-year number is the simplest way to lock in safe harbor because the prior-year number is a known, fixed amount.

How do I calculate quarterly estimated tax for freelance income?

Project your annual net self-employment income, subtract half of the self-employment tax and any above-the-line deductions (pre-tax retirement), apply the 2026 federal tax brackets to the remaining taxable income, add the full 15.3 percent self-employment tax on net earnings up to the Social Security wage base ($184,500 for 2026) plus 2.9 percent Medicare above, add state income tax, subtract any federal withholding from a W-2 or prior estimates, and divide the remainder by four. That is your per-quarter payment.

What happens if I miss a quarterly payment?

If your total withholding plus estimated payments falls below both safe harbor thresholds, the IRS charges an underpayment penalty calculated separately for each quarter on Form 2210. The current underpayment rate floats with the short-term AFR plus 3 percent (7 to 8 percent annualized in recent years). Penalty amounts are typically modest ($50 to $500 for a single missed quarter on a typical freelance income), not catastrophic, but they compound if multiple quarters are missed and interest accrues until paid.

How do I pay quarterly taxes to the IRS?

The IRS offers three fast ways: IRS Direct Pay at irs.gov/payments (free, direct from your bank account, no account required), the EFTPS system (requires enrollment, good for recurring), or a debit or credit card via an approved payment processor (fee applies). Most freelancers use IRS Direct Pay because it is free and can be scheduled a year in advance. State payments are made through the state's department of revenue or taxation website. Keep the confirmation numbers for every payment, they flow onto your Schedule 3 at tax time.

Can the 110% high-earner safe harbor rule trigger on the wrong year's income?

On this calculator, yes, and it is worth understanding why. The real IRS rule bases the 110% high-earner threshold on your PRIOR year's adjusted gross income exceeding $150,000. Since this calculator only collects your prior year's total tax dollar amount, not your prior year's AGI, it uses your CURRENT year's total income as a stand-in to decide whether the 110% rule applies. If your income spiked this year (say, from $90,000 last year to $200,000 this year), the calculator applies the 110% multiplier because current income exceeds $150,000, even though your actual prior-year AGI may have been well under that threshold and the true rule would only require 100%. On a $8,000 prior-year tax bill, that is the difference between an $8,000 and an $8,800 safe-harbor target. If your income changed significantly year over year, check your actual prior-year Form 1040 to see whether your AGI was really above $150,000 before trusting the 110% figure.