Estimated Quarterly Tax Calculator
Income & tax rate
Your result will appear here
Fill in the fields and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- United States — federal income and payroll tax, unless the calculator names a state or local levy
- Rules and time period
- Tax years supported by the selected calculator. Brackets, standard deductions and wage bases are re-set every year, and state and local rules are not modeled unless the page says so.
- Scope and limitations
- Educational estimate only, not a tax return, a filing determination or a withholding instruction. Confirm current law and your own facts with the IRS, your state authority or a qualified tax professional before filing or changing a W-4.
- Source links checked
- Sep 19, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
How to use
- 01
Enter your net self-employment income for the year — revenue after business expenses, not gross receipts. This is the figure your Schedule C produces, and it is what both income tax and self-employment tax are calculated from.
- 02
Set your effective tax rate. For most self-employed people this is not just the income tax bracket: self-employment tax adds 15.3% on the first portion of earnings, so a combined effective rate somewhere between 25% and 35% is a more realistic starting point than the bracket alone.
- 03
Open Advanced and enter tax already withheld from other jobs. Withholding from a W-2 counts toward your total liability, so a spouse's paycheck or your own part-time employment reduces what you need to send in yourself.
- 04
Read the annual tax, the amount per quarter and what to set aside monthly. The monthly figure is the practical one — quarterly deadlines are met by money that was put aside monthly, not found in April.
- 05
Check the four due dates: 15 April, 15 June, 15 September, and 15 January of the following year. They are not evenly spaced, and the second one arrives only two months after the first.
- 06
Compare your total against a safe harbour before relying on the estimate. Paying 100% of last year's tax — 110% if your prior-year AGI was over $150,000 — protects you from penalties even if this year turns out bigger than expected.
Formula
Estimated tax is an annual figure divided into four, less what has already been withheld: Annual tax = net self-employment income × effective rate Remaining = max(0, annual tax − withholding) Per quarter = remaining ÷ 4 Set aside monthly = remaining ÷ 12 The effective rate is doing a lot of work here, because a self-employed person owes two taxes at once. Self-employment tax is 15.3% — 12.4% for Social Security up to the annual wage base plus 2.9% for Medicare with no ceiling — charged on 92.35% of net earnings. Income tax is then charged on top, at your ordinary bracket, on the same earnings less the deductible half of the self-employment tax. That is why an employee in the 22% bracket and a freelancer in the 22% bracket do not owe the same amount on the same income. Setting aside 22% is one of the most reliable ways to be short in April.
Example
You expect $120,000 of net self-employment income and estimate a 30% effective rate covering both income tax and self-employment tax. Your annual liability is $36,000. Your spouse's job withholds $6,000 that counts toward your joint return, so $30,000 remains — $7,500 per quarter, or $2,500 a month set aside. The safe harbour check matters here. If last year's total tax was $28,000 and your prior-year AGI was under $150,000, paying $28,000 across the four installments protects you from an underpayment penalty even if this year finishes at $40,000. You would still owe the difference in April, but without a penalty on top. And if the income is uneven — most of it landing in the fourth quarter, as it does for many contractors — the annualised income installment method on Form 2210 lets you pay as you actually earn instead of in four equal parts.
Definitions
- Estimated tax
- Tax paid in installments during the year on income that has no withholding — self-employment, investments, rent, or a large one-off gain.
- Form 1040-ES
- The worksheet and payment vouchers for estimated tax. Payments can also be made electronically without using the vouchers.
- Net self-employment income
- Business revenue less deductible business expenses — the bottom line of Schedule C. Estimated tax is built from this, not from gross receipts.
- Self-employment tax
- 15.3% covering both halves of Social Security and Medicare: 12.4% up to the annual wage base plus 2.9% with no ceiling. Charged on 92.35% of net earnings.
- Effective tax rate
- Your total tax divided by your income — the blended figure across income tax and self-employment tax that this calculator asks for.
- Safe harbour
- A payment level that prevents an underpayment penalty regardless of how the year ends: generally 90% of the current year's tax or 100% of last year's, rising to 110% if prior-year AGI exceeded $150,000.
- Underpayment penalty
- Interest-like charge for paying too little too late, calculated per quarter on Form 2210. Paying the annual total late does not cure an early shortfall.
- Quarterly due dates
- 15 April, 15 June, 15 September, and 15 January of the following year. The periods they cover are three, two, three and four months — not four equal quarters.
- Annualised income installment method
- A Form 2210 method that lets people with uneven income pay in proportion to what they actually earned each period rather than in four equal installments.
- Withholding
- Tax already taken from a paycheck. It counts toward your total liability, and unlike estimated payments it is treated as paid evenly through the year whenever it was actually withheld.
- Schedule C
- The form reporting profit or loss from a sole proprietorship. Its bottom line feeds both income tax and self-employment tax.
- Schedule SE
- The form computing self-employment tax, including the deductible half that reduces your income tax.
- Deductible half of SE tax
- Half your self-employment tax is deducted in arriving at adjusted gross income, which lowers income tax but not the self-employment tax itself.
- Quarterly set-aside
- The practice of moving a fixed percentage of every payment received into a separate account as it arrives. The reliable alternative to finding the money at the deadline.
Good to know
Why the self-employed pay quarterly at all
The United States tax system is pay-as-you-go. An employee satisfies that automatically: their employer withholds income tax and payroll tax from every paycheck and remits it, so by the time the return is filed the tax is largely paid. Self-employment removes the mechanism, not the obligation. Income arrives without withholding, and the requirement to pay through the year remains. Estimated tax is how a self-employed person does what an employer does for an employee. The threshold is low. If you expect to owe $1,000 or more when you file, after subtracting withholding and refundable credits, estimated payments are generally required. Most people clear that in their first profitable year of freelancing. It is not only the self-employed. Substantial investment income, rental income, a large capital gain, retirement withdrawals without adequate withholding, or income from a partnership or S corporation all create the same obligation. The consequence of ignoring it is not a fine in the ordinary sense — it is an underpayment penalty calculated like interest on what should have been paid and was not, computed period by period. Paying the full amount late does not cure an early shortfall, because each period is assessed on its own. Understanding this rhythm changes how self-employment feels financially. Income arrives gross and a meaningful share of it is not yours. Treating every payment received as fully available is the origin of most April crises, and the solution is mechanical rather than clever: move the tax share out of reach the day the money lands. There is a psychological dimension worth naming, because it explains why capable people still get this wrong. Employment hides the tax: the salary you negotiate is gross, but the money that arrives is net, so spending what arrives is safe. Self-employment removes that buffer — everything arrives gross and looks like income. The failure is not one of arithmetic but of the default. Rebuilding the buffer deliberately, by moving the tax share out on arrival, restores the safety that employment provided automatically and is the single change that most reliably prevents an April problem.
Two taxes at once, and why your bracket understates the bill
The most expensive misunderstanding in self-employment tax is thinking about income tax alone. A self-employed person owes both income tax and self-employment tax. Self-employment tax is Social Security and Medicare — the same contributions an employee makes — except that an employee pays half and the employer pays the other half, while a self-employed person pays both. That is 15.3% in total: 12.4% for Social Security up to the annual wage base, and 2.9% for Medicare with no upper limit, plus an additional 0.9% Medicare surtax above certain thresholds. It is charged on 92.35% of net earnings, an adjustment that approximates the employer-side deduction an employee's wages effectively receive. Half of the resulting self-employment tax is then deductible in arriving at adjusted gross income, which reduces income tax but not the self-employment tax itself. Stack the two and the arithmetic changes character. Someone in the 22% income tax bracket faces roughly 22% plus an effective self-employment burden in the low teens after the adjustments — a combined effective rate that can approach or exceed 30%. Add state income tax and it goes higher still. This is why setting aside 22% because you are "in the 22% bracket" reliably leaves people short. The bracket describes one of two taxes. It is also why the effective rate this calculator asks for should be a blended figure covering both, and why 25% to 30% is a more realistic starting assumption than any income tax bracket alone. The wage base is worth watching for higher earners because it creates a step in the effective rate. Social Security stops applying above an annual wage base that is indexed each year, so income above it attracts only the 2.9% Medicare component rather than the full 15.3%. Someone earning well above the base has a materially lower marginal self-employment burden on their later dollars than on their first ones — which means a single blended effective rate overstates the tax on additional income late in a strong year and understates it early.
The four dates, and the fact that they are not quarters
Estimated tax payments are due on 15 April, 15 June, 15 September, and 15 January of the following year, each shifting to the next business day when it falls on a weekend or holiday. Despite the name, these are not quarterly. The periods they cover are three months, two months, three months and four months. The first payment covers January through March, the second covers April and May only, the third covers June through August, and the fourth covers September through December. That second payment is where budgeting goes wrong. Someone who paid in April and set a three-month reminder discovers the next deadline arrived a month early. Sixty days after the first payment, another equal amount is due, covering a shorter period. The fourth payment falling in January of the following year has its own trap: it is easy to think of it as next year's problem when it belongs to the year just ended. Missing it produces a penalty for the final period even if the return is filed and paid on time in April. Payments can be made electronically, which is faster and produces a record, or by post with the vouchers from Form 1040-ES. The date that matters is the date paid, and electronic payment removes any argument about postmarks. The practical arrangement that works is not remembering four dates. It is moving a fixed percentage of each payment received into a separate account as it arrives, so the money is already segregated when the deadline comes and the only remaining decision is transferring it. The uneven period lengths also affect how a shortfall is measured. Because the penalty is computed per period, missing the June payment costs interest from June, not from the following April. Someone who realizes in October that they have underpaid all year is already accruing on three periods. The practical response is to pay as soon as the shortfall is identified rather than waiting for the next scheduled date — the penalty stops accruing when the money arrives, and there is nothing to be gained by aligning a catch-up payment with a deadline.
Safe harbours: the most useful rule in estimated tax
You are not required to predict your income accurately. You are required to pay enough, and the safe harbour rules define enough in a way that removes the guesswork. No underpayment penalty applies if you pay, through withholding and timely estimated payments, either 90% of the current year's total tax or 100% of the prior year's total tax — rising to 110% of the prior year if your prior-year adjusted gross income exceeded $150,000. The prior-year option is the powerful one, because last year's tax is a known number sitting on a return you already filed. Divide it by four, pay it on schedule, and you are protected regardless of how this year turns out. If this year is far better, you will owe the difference in April — but without a penalty on top of it. That is exactly the situation where estimated tax is hardest: a year when income rises sharply and unpredictably. The prior-year safe harbour turns an unanswerable forecasting problem into arithmetic. It cuts the other way too. In a year when income falls substantially, paying 100% of a large prior-year tax means significantly overpaying and waiting for a refund. There the 90%-of-current-year test is the better target, accepting that it requires a real estimate. One detail is worth knowing because it can rescue a bad situation. Withholding is treated as paid evenly throughout the year, no matter when it actually occurred. Someone who has underpaid through three quarters can increase withholding from a job — their own or a spouse's on a joint return — late in the year, and that withholding is credited as though it had been spread across all four periods. An estimated payment made in December gets no such treatment. One caution about the prior-year safe harbour: it protects against penalties, not against the bill. A year in which income doubles will still produce a large balance due in April, and paying only last year's tax through the year means the whole increase lands at once. The safe harbour is best used as a floor rather than a target — pay at least that much to be protected, and set aside more against the actual liability, so the April payment is funded rather than merely penalty-free.
Uneven income and the annualised method
The default assumption is that income arrives evenly and four equal payments are appropriate. For a great many self-employed people that is simply false. A consultant who signs one large contract in October, a seasonal business that earns most of its money in summer, someone who sells a property in November — all face the same problem. The standard method expects a payment in April on income that will not exist until much later, and failing to make it produces a penalty for the early periods even though the total for the year is paid in full and on time. The annualised income installment method solves this. Rather than dividing an annual estimate into four, it computes the required payment for each period based on what you actually earned by the end of that period, annualised. Earn nothing in the first quarter and the first required payment is nothing. Earn most of the year's income in the fourth quarter and the obligation appears then. It is claimed on Form 2210, Schedule AI, with the return. It requires knowing your income and deductions period by period rather than only annually, which is more work — but it is the difference between a penalty and none for anyone whose income is genuinely lumpy. The practical requirement is bookkeeping that can produce a profit figure at each of the four cut-off dates rather than only at year end. For most people that means keeping accounts current through the year, which is worth doing regardless. If your income is uneven and you have been paying equal installments and absorbing penalties, this method is usually the fix, and it is applied when filing rather than requiring anything in advance. The annualised method has one further practical benefit that is often overlooked: it forces a real look at profitability four times a year. Producing the figures the method needs means closing the books quarterly, which surfaces problems — an unprofitable line of work, expenses drifting upward, invoices unpaid — while there is still time in the year to respond. Many self-employed people who adopt it for tax reasons keep it for management reasons, because quarterly numbers change decisions in a way an annual return never can.
How much to set aside, and the account that makes it work
The mechanics that survive contact with reality are simple and slightly boring. Open a separate account for tax. Not a mental earmark inside the operating account — a distinct account, ideally at a different institution so it is not visible when you check your balance and not one transfer away from being spent. Move a fixed percentage of every payment received into it, on the day it arrives. Between 25% and 30% is a reasonable starting point for federal tax on self-employment income; add your state's rate on top if it has one. Higher earners should use more. Pay the four installments from that account and leave the remainder to accumulate. The balance should grow, because the set-aside percentage is deliberately conservative, and the surplus absorbs the year being better than expected. What makes this work is that it removes the decision. The alternative — deciding at each deadline how much to send, from a balance that also has to cover rent — fails predictably, not because people are undisciplined but because the money is fungible and the deadline is distant. Review the percentage once or twice a year against actual results. If the account balance is far larger than the remaining liability, the rate is too high and is starving the business of working capital. If it is short before every deadline, raise it. And remember the deductible expenses that reduce the base: business costs, the deductible half of self-employment tax, retirement contributions through a SEP-IRA or solo 401(k), and the self-employed health insurance deduction. These reduce what you owe, which means the set-aside can be lower — but only if you actually track them. It is also worth building the set-aside around a percentage of revenue rather than of profit, at least at first. Profit is not known until expenses are recorded, and expenses are recorded late; revenue is known the moment money arrives. Setting aside a slightly lower percentage of every payment received, immediately, is more robust than a precise percentage of a profit figure calculated monthly in arrears — and the surplus that builds up when expenses turn out higher than expected is exactly the buffer that makes the system survive a bad quarter.
State estimated tax, and the second set of deadlines
Most states with an income tax require their own estimated payments, with their own forms, their own thresholds and their own deadlines. Many mirror the federal dates; some do not, and a few use different period definitions entirely. State rates vary enormously — from nothing at all in a handful of states to figures approaching double digits at the top in others. For someone in a high-tax state, the state obligation can be a third or more of the total, and it is a common omission because the federal calculation feels like the whole job. Safe harbour rules generally exist at state level too, but the thresholds and percentages are not always the same as the federal ones. A payment level that protects you federally may not protect you at state level. There are additional wrinkles for people whose work crosses state lines. Income can be taxable where it is earned as well as where you live, with a credit mechanism intended to prevent double taxation that does not always cover it fully. Remote workers serving clients in other states, and anyone who moved mid-year, can face genuine complexity here. Some states also levy local income taxes at city or county level, with yet another set of rules. The effective rate this calculator asks for is a single blended figure, so the practical approach is to include your state rate in it — or to run the calculator twice, once for federal and once for state, and add the results. What matters is that the state obligation is planned rather than discovered, because state underpayment penalties apply on the same logic as federal ones. Anyone working across state lines should also check whether their state requires payments on a different schedule, because a mismatch is easy to miss. Some states use the same four dates; some combine periods; a few use different due dates entirely. Setting a single reminder for the federal dates and assuming the state follows is one of the more common ways an otherwise organized person accrues a state penalty on money they had already set aside and were perfectly willing to pay.
What this calculator does not model
This tool takes a net income figure and an effective rate, subtracts existing withholding, and divides the remainder into four. That is the right shape for steady income and it produces a usable set-aside target. It does not compute your tax. It does not calculate self-employment tax from your net earnings, apply the 92.35% adjustment, or find the Social Security wage base. It does not run your income through the tax brackets, apply the standard deduction, or handle the qualified business income deduction that can reduce taxable business income by up to 20%. The effective rate you enter carries all of that, which makes the quality of that single input the main determinant of the answer. It divides into four equal parts, which is wrong for uneven income — the annualised method exists precisely because that assumption fails, and it is not modeled here. It does not check your figures against the safe harbours. That check is worth doing manually: find last year's total tax on your return, multiply by 1.0 or 1.1 depending on your prior-year AGI, and compare. It does not model state or local estimated tax, retirement plan contributions, the self-employed health insurance deduction, or credits. Use it for what it is good at: converting an annual expectation into a monthly set-aside and a quarterly payment, so the number has a place in your budget rather than arriving as a surprise. For the actual figures, Form 1040-ES has the worksheet, and an accountant is worth the fee in the first year of self-employment — largely because they will find deductions that change the effective rate you should have been using all along. Finally, the first year deserves particular care, because there is no prior-year figure to fall back on. Someone who was employed all of last year has a prior-year tax that reflects withholding on a salary, which may bear no relation to a new self-employed liability — and someone with no prior return at all cannot use the prior-year safe harbour, leaving only the 90%-of-current-year test, which requires a genuine estimate. That makes the first year the one where a genuine estimate matters most, and the one where an accountant earns their fee fastest, because they will also identify the deductions that change the effective rate you should be using from then on.
Frequently asked questions
Do I have to pay quarterly estimated tax?
Generally yes if you expect to owe $1,000 or more when you file, after subtracting withholding and credits. That threshold catches most self-employed people from their first profitable year. If your only income is a salary with adequate withholding, you do not need to.
What are the actual due dates?
15 April, 15 June, 15 September, and 15 January of the following year, with each shifting to the next business day if it falls on a weekend or holiday. They are not evenly spaced — the second payment arrives two months after the first, which catches out people budgeting on a strict three-month rhythm.
What happens if I miss a payment?
You are charged an underpayment penalty for that period, computed like interest on the shortfall for the time it went unpaid. Paying extra later does not fully cure an earlier miss, because the penalty is calculated quarter by quarter. Catching up is still worth doing — it stops the charge growing — but it does not erase what has accrued.
What is the safe harbour and why does it matter?
It is a level of payment that prevents any penalty regardless of how the year turns out: 90% of this year's tax, or 100% of last year's total — 110% if your prior-year AGI exceeded $150,000. The second option is the powerful one, because last year's figure is a known number. In a year when your income rises sharply, paying last year's tax in four installments protects you completely while you sort out the difference by April.
Why is my tax rate higher than my bracket?
Because you owe two taxes. Self-employment tax adds 15.3% on 92.35% of your net earnings, on top of income tax at your ordinary bracket. Someone in the 22% bracket can face a combined effective rate near 35% on self-employment income. Setting aside your bracket percentage is the single most common reason freelancers are short in April.
How much should I set aside from each payment?
A common rule of thumb is 25% to 30% of every payment received, moved to a separate account the day it arrives. Higher earners and those in states with income tax should use more. The rule works not because the percentage is precise but because it removes the decision — the money is gone before it can be spent.