Quarterly Tax Calculator
Self-employed workers, freelancers, and independent contractors are required to pay estimated taxes quarterly to the IRS. This quarterly tax calculator helps you determine how much to set aside for each payment period based on your projected annual self-employment income and business expenses. Avoid underpayment penalties by planning ahead — enter your expected income and deductions below to see a breakdown of your quarterly estimated tax payments for 2026, including self-employment tax and federal income tax.
How This Calculation Works
Your net self-employment income is calculated by subtracting business expenses from gross income. Self-employment tax (15.3%) is applied to 92.35% of net income. Half of the SE tax is deductible for income tax purposes. Federal income tax is calculated on your adjusted taxable income after the SE deduction and standard deduction ($16,100 for single filers, 2026). The total annual tax is divided equally across four quarterly payments due in April, June, September, and January. Making these payments on time helps you avoid IRS underpayment penalties.
Who Has to Pay Quarterly Estimated Taxes
The US tax system is pay-as-you-go. Employees satisfy that through payroll withholding; everyone else must send the money themselves. You generally owe estimated payments if you expect to owe $1,000 or more when you file, after subtracting withholding and refundable credits.
- Freelancers, contractors and gig workers with 1099 income.
- Sole proprietors, single-member LLC owners, partners and S-corporation shareholders.
- Landlords with net rental income and investors with large capital gains or dividends.
- Retirees taking distributions without withholding elected.
- Employees whose withholding falls short — often two-income households or people with large bonuses.
2026 Due Dates and What Each Period Covers
| Payment | Income period | Due (approximate) |
|---|---|---|
| Q1 | 1 January – 31 March | 15 April |
| Q2 | 1 April – 31 May | 15 June |
| Q3 | 1 June – 31 August | 15 September |
| Q4 | 1 September – 31 December | 15 January of the following year |
The periods are deliberately uneven — Q2 covers two months, Q3 covers three. When a due date falls on a weekend or federal holiday it shifts to the next business day. Filing your annual return by 31 January can replace the January instalment if you pay the balance in full.
How Much to Send: the Safe Harbour Rules
You avoid an underpayment penalty by meeting either test below, even if you ultimately owe more at filing.
- 90% of the current year's total tax liability, paid across the four instalments; or
- 100% of last year's total tax — 110% if your prior-year adjusted gross income exceeded $150,000.
The prior-year rule is the practical choice for anyone with unpredictable income: take last year's total tax, divide by four, and pay that amount regardless of how the current year develops. If income is growing quickly, the 90% current-year test avoids overpaying — but requires an updated projection each quarter, which is what the calculator above provides.
What counts toward the total
Include federal income tax, self-employment tax of 15.3% on 92.35% of net profit, the 0.9% additional Medicare tax where applicable, and the net investment income tax on higher investment income. State estimated payments are separate and follow each state's own schedule and thresholds.
The Penalty for Missing a Payment
The underpayment penalty is effectively interest charged on each quarter's shortfall for the days it remained unpaid, at a rate the IRS resets quarterly. It is not a flat fine, so a payment made two weeks late costs very little, while an unpaid Q1 amount accrues for roughly nine months.
- Paying late is always better than not paying — the charge accrues daily.
- Withholding is treated as paid evenly across the year, so increasing W-4 withholding late in the year can cure earlier quarters.
- The annualized income method (Form 2210, Schedule AI) reduces or removes the penalty when income was genuinely earned late in the year.
- Waivers exist for retirement at 62+, disability, casualty and other reasonable cause.
- There is no penalty if your total tax after withholding is under $1,000, or if you had no tax liability last year.
Quantify a shortfall with the estimated tax penalty calculator.
How and Where to Pay
- IRS Direct Pay — free bank transfer, no registration, immediate confirmation.
- EFTPS — free, requires enrolment, best for scheduling all four payments in advance.
- Debit or credit card through an approved processor — convenient but carries a fee of roughly 2%.
- Form 1040-ES by mail with a cheque, postmarked by the due date.
- State payments go through your state revenue department's own portal — do not assume the IRS forwards anything.
A system that makes this painless
Open a separate savings account for tax. Transfer 25–30% of every business payment the day it arrives, and never touch it for operating expenses. When a due date approaches, the money is already there and the payment becomes a two-minute administrative task rather than a cash-flow event.
Project your annual liability first with the self-employed tax calculator or the 1099 tax calculator, then divide it across the four periods above.