Quarterly Tax Calculator 2026
Estimate your 1040-ES quarterly tax payments. Avoid IRS underpayment penalties.
Your Quarterly Payment Schedule
How quarterly estimated taxes work
The short answer
You owe quarterly estimated payments if you expect to owe $1,000 or more in federal tax — roughly $8,000 of net profit. Paying 100% of last year's tax (110% if your AGI was over $150,000) protects you from any underpayment penalty, however much you ultimately owe.
The deadlines, which are not quarters
| Payment | Income period | Due |
|---|---|---|
| Q1 | 1 January – 31 March | 15 April |
| Q2 | 1 April – 31 May | 16 June |
| Q3 | 1 June – 31 August | 15 September |
| Q4 | 1 September – 31 December | 15 January of the following year |
Q2 covers two months, not three, and its deadline falls two months after Q1 rather than three. It is the one people miss. Q4's payment is due in January, after the year it relates to has ended.
The safe harbour, and why it matters more than accuracy
You cannot know your annual profit in April, and the IRS does not require you to. Pay either 90% of this year's total tax or 100% of last year's — 110% if last year's adjusted gross income exceeded $150,000 — and no underpayment penalty applies regardless of how far off your estimate turns out to be.
When income is rising, the prior-year test is the one to use: it is a fixed number you already have from last year's return, rather than a forecast of a year you have not lived. You will owe the balance in April, but you will owe no penalty on it.
What the penalty costs if you miss
It is interest, not a fine: the federal short-term rate plus three percentage points, charged on each quarter's shortfall from that quarter's due date. Two things follow. Small shortfalls cost little — people routinely overestimate this. And because it accrues per quarter, a large catch-up payment in Q4 does not repair a Q1 shortfall.
If your income genuinely arrived late in the year, Schedule AI of Form 2210 lets you show the IRS when it arrived and recompute each quarter's requirement. It is tedious but it can eliminate the penalty entirely for seasonal or project-based work.
How to pay
- IRS Direct Pay — free, straight from a bank account, no registration.
- EFTPS — free, requires enrolment that takes several days, better for scheduling payments ahead.
- Card — accepted, but the processor fee is around 1.8%, which on a $4,000 payment is $72 for no benefit.
- State — most states with an income tax run their own portal on the same schedule. They are separate payments; paying the IRS does not pay your state.
Frequently asked questions
Frequently Asked Questions
Do I have to pay quarterly taxes as a freelancer?
What happens if I pay late or skip a quarter?
How much should I pay each quarter?
Do I pay state estimated taxes too?
Sources
- IRS Revenue Procedure 2025-32 — 2026 inflation adjustments — tax brackets, standard deduction, QBI thresholds.
- IRS Schedule SE instructions — Self-employment tax: the 92.35% adjustment, the Social Security wage base, the Medicare surtax.
- IRS Form 1040-ES — Estimated tax deadlines and the safe-harbour rules used for the quarterly schedule.
- IRS Publication 334 — Tax guide for small business — deductible expenses and net profit.
- IRS Social Security wage base — The $184,500 Social Security cap applied for 2026.
How these numbers are produced
Calculations follow the order of operations on the IRS forms themselves: net profit, the 92.35% adjustment, self-employment tax, the 50% deduction against AGI, the standard deduction, the §199A QBI deduction with its phase-out, then the federal brackets. State tax is computed separately on state AGI less that state's own standard deduction, because no state allows the federal QBI deduction and almost none allow the federal standard deduction.
What it does not cover. The calculators model a single filer or a married couple filing jointly with self-employment income as the main source. They do not model local income taxes, W-2 wages held alongside freelance work, itemized deductions, the alternative minimum tax, or credits. Where a local income tax exists, it is described on that state's page.
Not advice. SelfTaxCalc produces estimates, not tax advice. No one here is a CPA, an enrolled agent or a tax attorney, and nothing on this site creates a professional relationship. Estimates are a starting point for planning and for a conversation with a professional — they are not a substitute for one.