Quarterly Tax Calculator
Estimate your annual tax, subtract what you have already paid through withholding and prior payments, and get a suggested quarterly estimated payment. For self-employed and other estimated-payment taxpayers.
Written by the CalcBundle Research & Editorial Team · Reviewed by the Quality Review Team · Transparent formulas · results are estimates, not advice. · Updated
Suggested quarterly payment
Enter your estimated annual income.
Quick Answer
How do quarterly estimated taxes work?
Self-employed workers and freelancers who expect to owe $1,000 or more in federal tax must make quarterly estimated payments to the IRS — due April 15, June 15, September 15, and January 15. Each payment covers roughly one quarter of estimated annual tax: federal income tax on net profit plus self-employment tax (15.3% on the first $176,100 of net SE income in 2025, 2.9% above that). The safe harbor rule lets you avoid the underpayment penalty by paying 100% of last year's total tax liability in four equal installments (110% if prior-year AGI exceeded $150,000). A freelancer with $80,000 net profit owes approximately $18,000–$21,000 in federal tax, split into payments of roughly $4,500–$5,250 each quarter. This calculator estimates the quarterly amount from annual income, business expenses, filing status, and prior-year tax — and shows the SE tax and income tax components separately so you know what you are actually paying.
What a quarterly tax calculator does
Taxes in most systems are pay-as-you-go: the government expects its share as you earn, not in a single payment at filing. Employees meet this automatically through withholding, but anyone earning income that is not withheld has to send the money themselves, in instalments. A quarterly tax calculator estimates your yearly tax, credits what you have already paid, and splits the rest into manageable payments — so the obligation becomes a predictable line in your budget instead of a shock at the end of the year.
Start with the annual estimate
The suggested payment is only as good as the annual figure behind it. That figure combines your expected income tax — based on all your income, deductions and credits — with self-employment tax if you work for yourself. Estimating the year first, then dividing, is far more accurate than guessing a flat amount, because it accounts for how your income stacks through the brackets.
Credit what you have already paid
You rarely owe the whole annual amount in estimates. Tax withheld from a W-2 job, a spouse's withholding on a joint return, and any estimated payments you have already made all reduce the balance. The calculator subtracts these before dividing, so you are not double-paying tax that an employer is already handling — a common reason people over-pay their estimates.
Splitting the balance
The remaining estimated tax is divided across the remaining payment periods to give a per-period figure. If you are starting mid-year or your income is uneven, the payment can be weighted to when income is actually earned rather than spread flatly. The goal is simply to have paid enough, evenly enough, to stay inside the safe harbor and avoid an underpayment penalty.
Worked example
Suppose your estimated annual tax is $16,000, and $4,000 has already been withheld from a part-time W-2 job. That leaves $12,000 to cover through estimates; divided across four periods, the suggested payment is about $3,000 each. If you make a large sale later in the year, you would re-run the estimate and top up the remaining payments rather than wait until filing.
Build the habit with related tools
Quarterly payments are easiest when you set money aside as it comes in. Use the 1099 tax calculator to decide the percentage to hold back from each client payment, and the self-employment tax calculator and income tax calculator to sharpen the annual estimate. Keep the estimate here distinct from the actual liability on your filed return.
Frequently asked questions
Who pays quarterly estimated taxes?
Anyone with income that is not fully covered by withholding — self-employed workers, freelancers and contractors, investors with large gains or dividends, landlords, and people with significant side income — generally makes estimated payments through the year to cover income tax and, where it applies, self-employment tax.
How is the quarterly payment estimated?
The calculator estimates your annual tax (income tax plus self-employment tax where relevant), subtracts amounts already withheld and any estimated payments you have already made, and divides the remaining balance by the number of remaining periods. The result is a suggested payment, not an official figure.
When are estimated payments due?
In the US, estimated tax is typically due in four instalments across the year rather than once at filing. Exact dates shift year to year and can be affected by weekends and holidays, so confirm the current deadlines with the tax authority before you rely on them.
What is the safe harbor?
Many systems let you avoid an underpayment penalty if you pay at least a set percentage of last year's tax or of this year's actual tax, whichever rule applies to you. Paying to a safe harbor protects you even if your income turns out higher than expected. Rules and percentages vary, so verify them for your situation.
What happens if I underpay?
Paying too little through the year can trigger an underpayment penalty, effectively interest on the tax you should have paid earlier. Paying evenly and to a safe harbor avoids it. If your income is uneven, some taxpayers use an annualised method to match payments to when income was actually earned.
Does this guarantee I will not owe a penalty?
No. Safe-harbor rules, deadlines and thresholds vary by jurisdiction and change over time, and your final liability depends on your complete return. Treat the suggested payment as a planning estimate and verify the requirements for your jurisdiction and tax year — this is not tax advice.
Related calculators
Sources & methodology
- Formula
- Quarterly Payment = (Estimated Annual SE Tax + Estimated Income Tax − Credits) ÷ 4; Safe Harbor = Prior Year Total Tax ÷ 4 (or ÷ 4 × 1.1 if prior AGI > $150,000)
- Reviewed
- September 2026
Primary sources
- IRS Publication 505 – Estimated Tax for IndividualsOfficial IRS guidance on who must pay estimated tax, how to calculate each quarterly payment, and safe harbor rules.
- IRS Form 1040-ES – Estimated Tax for IndividualsOfficial IRS form and worksheet for computing quarterly estimated tax payments, including the SE tax deduction.
- IRC §6654 – Failure to Pay Estimated Income TaxInternal Revenue Code section defining the underpayment penalty threshold and safe harbor exceptions for estimated tax.
Calculation methodology is documented on our methodology page. Reviewed by the CalcBundle Quality Review Team.
Disclaimer. This calculator provides estimates for informational purposes only. Results are based on the information you enter and the assumptions used by the calculator. Actual financial, tax, business valuation, lending, marketplace or investment outcomes may differ. Consider consulting a qualified professional for decisions involving significant amounts of money. Estimated payments and deadlines can vary. Verify applicable requirements for your jurisdiction and tax year — this does not guarantee penalty avoidance and is not tax advice.