Estimated Quarterly Tax Calculator for the Self-Employed (2026)

To calculate your estimated quarterly tax as a self-employed worker, multiply your net business income by 92.35%, apply the 15.3% self-employment tax rate plus your income tax bracket, then split the total into four payments due April 15, June 15, and September 15, 2026, and January 15, 2027. Below is a step-by-step worksheet you can fill in with your own numbers right now, followed by the IRS safe-harbor rule that decides whether you'll owe a penalty if the estimate is off.

How the calculator works

An estimated quarterly tax calculator for the self-employed runs the same three steps every time: it finds your taxable net income, applies the self-employment tax rate plus your income tax bracket, and divides the annual total into four payments tied to the IRS calendar. Use the worksheet below as your calculator — fill in the "Your number" column with your own figures as you go.

This worksheet mirrors the logic behind Form 1040-ES (IRS, About Form 1040-ES). It won't replace a full tax return, but it gets you a real number to send with each quarterly payment today.

What counts as net self-employment income

Your starting point is net profit from Schedule C (or your LLC's P&L if you're a single-member LLC taxed as a disregarded entity): total self-employment income minus ordinary, necessary business expenses. The IRS then requires you to multiply that net profit by 92.35% before applying the self-employment tax rate — this accounts for the employer-equivalent portion of SE tax being deductible (IRS, Estimated Taxes).

Example, for illustration only: a freelance designer with $80,000 in net Schedule C profit has net earnings subject to SE tax of $80,000 × 92.35% = $73,880.

15.3% self-employment tax + your income tax bracket

Self-employment tax is a flat 15.3%, made up of two parts:

• 12.4% for Social Security, applied only up to the annual Social Security wage base limit set by the SSA each year.
• 2.9% for Medicare, applied to all net self-employment earnings with no cap.

If your combined wages and self-employment income exceed $200,000 (single) or $250,000 (married filing jointly), an additional 0.9% Medicare surtax applies on the excess (IRS, About Form 1040-ES). On top of SE tax, you still owe regular federal income tax on your net profit at your marginal bracket, plus any state income tax where applicable. One important distinction: this 15.3% calculation applies to Schedule C income, single-member LLCs taxed as disregarded entities, and partnership self-employment earnings — it does not apply to S-corporation shareholder distributions, which follow a different set of rules (see the FAQ below).

Continuing the example: $73,880 × 15.3% = $11,304 in self-employment tax (half of this, $5,652, is deductible on Form 1040). Add an estimated federal income tax liability based on your bracket and deductions, and a state tax if your state levies one, to get your total estimated tax for the year.

2026 payment due dates (Apr 15, Jun 15, Sep 15, Jan 15 2027)

Note the periods aren't equal thirds of the year — Q2 covers two months and Q4 covers four. If a due date falls on a weekend or federal holiday, the payment is on time if made the next business day — the same rule that affects the exception below.

There's one exception worth knowing: if you file your 2026 tax return and pay your entire remaining balance by February 1, 2027, you don't have to make the January 15, 2027 payment at all. That date isn't a typo — the statutory deadline is January 31, but since January 31, 2027 falls on a Sunday, the IRS's weekend rule pushes it to the next business day, Monday, February 1, 2027 (IRS, Estimated Taxes). It only works if the return is filed and the full balance is paid by that date — a partial payment plus a late return doesn't qualify.

The IRS safe-harbor rule, explained

The IRS safe-harbor rule says you avoid an underpayment penalty if you pay, across the year, at least 90% of your current year's tax liability or 100% of last year's tax liability (110% if your prior-year adjusted gross income was over $150,000, or $75,000 if married filing separately). You only need to satisfy one of the two thresholds, not both.

• 90% of current-year tax — accurate but requires forecasting income you may not have yet.
• 100% of prior-year tax — simplest if your income is stable.
• 110% of prior-year tax — required instead of the 100% rule once prior-year AGI exceeded $150,000.

This is why a calculator that only looks at today's numbers can mislead you: if your income jumps mid-year, the safe 90%-of-current-year figure moves too, even though the 100%/110% prior-year floor stays fixed.

What happens if you skip a quarterly payment

If you miss a quarterly payment or pay less than the safe-harbor amount for that period, the IRS charges an underpayment penalty calculated separately for each quarter on Form 2210. This isn't a flat daily interest charge you can eyeball — the IRS sets an underpayment rate every calendar quarter (the federal short-term rate plus three percentage points), and that rate applies to each day your shortfall remains unpaid, from that installment's due date until it's paid or until the rate resets the following quarter. Because the rate itself can change partway through your underpayment period, the exact penalty depends on the published IRS rate tables for the quarters involved, not a single fixed percentage. Paying your full annual tax by the April filing deadline does not erase penalties already accrued on earlier quarters. If you genuinely owed little or no tax last year, or you just started self-employment income this year, you may qualify for an exception — check Form 2210's instructions or talk to a tax advisor before assuming you're penalty-free.

Calculate once, pay on autopilot

Why a static calculator isn't enough once your income changes mid-year

Every public calculator — ours included, if used in isolation — takes a snapshot: the income you type in on the day you use it. The problem is that self-employment income rarely looks the same in Q1 and Q3. A freelancer who lands a big client in June needs a different Q3 payment than the one calculated in January, and the safe-harbor math changes with it. Re-running the worksheet above four times a year works, but only if you remember to do it and your bookkeeping is current enough to trust the inputs.

How Kangaroo ERP recalculates from your real bookkeeping

Kangaroo ERP's tax engine uses the income and expenses already recorded in your books to estimate your suggested quarterly payment, instead of asking you to re-type numbers into a separate spreadsheet every few months. We recommend checking that estimate against the safe-harbor thresholds above each quarter, especially right after a change in income, so the number you send the IRS reflects where your year actually stands. If you're comparing how an LLC's self-employment tax stacks up against electing S-corp status, our self-employment tax vs. S-corp calculator breakdown walks through that decision in more depth. If you want your quarterly number tied to your real books before the next deadline, you can start a Kangaroo ERP trial.

FAQ

Quick answers to the questions we hear most often from freelancers and 1099 workers figuring out quarterly taxes for the first time.

Informational content. It does not replace professional advice on your specific case.

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