Quarterly Estimated Tax Calculator

About this calculator

A free 2026 quarterly estimated tax calculator for freelancers and the self-employed, following the IRS Form 1040-ES method: self-employment tax of 15.3% on 92.35% of net profit, then federal income tax on income after the deductible half of SE tax and the standard deduction. A single filer with $90,000 of net profit owes $12,716.60 of SE tax plus $9,571.17 of income tax — $22,287.77 total, paid as four installments of $5,571.94. A safe-harbor view computes the minimum payments that avoid an underpayment penalty using last year's tax. Constants come from IRS Rev. Proc. 2025-32 and the 2026 Social Security wage base, with disclosed simplifications (standard deduction only, no QBI deduction or credits). A planning estimate — not tax advice or a filing tool.

Why freelancers owe tax four times a year

The U.S. income tax is pay-as-you-go: employees prepay through withholding, and people with untaxed income — freelance profit, gig work, 1099 contracting — prepay through quarterly estimated payments due roughly April 15, June 15, September 15, and January 15. Skip them and the IRS charges an underpayment penalty computed like interest, even if you pay the full bill at filing.

The calculator sizes those four payments from your expected annual numbers: estimate the year's total tax, subtract any withholding you already have (from a W-2 job, say), and divide what's left by four.

Self-employment tax comes first

Self-employment tax is the freelancer's version of FICA — 12.4% Social Security plus 2.9% Medicare, both halves, applied to 92.35% of net profit per Schedule SE. On $90,000 of profit the base is $83,115 and the tax is $12,716.60 ($10,306.26 Social Security + $2,410.34 Medicare). It applies from the first dollar of profit, which is why even modest side income generates a real tax bill before income tax enters the picture.

Two reliefs are built into the method and the calculator: W-2 wages you also earn use up the $184,500 Social Security wage base first, and half the SE tax is deducted before income tax is computed — worth $6,358.30 off the $90,000 filer's taxable income.

Then income tax on what's left

Adjusted gross income is profit plus other income minus the deductible half of SE tax; the 2026 standard deduction ($16,100 single, $32,200 married filing jointly per IRS Rev. Proc. 2025-32) comes off next, and the marginal brackets apply to the rest. The $90,000 filer lands at $67,541.70 of taxable income and $9,571.17 of income tax — a 14% average rate even though their top bracket is 22%.

Stack the two layers and the working total for planning is roughly 25% of net profit at this income level. The calculator does the layered math exactly so you can stop guessing with flat percentages — and so a raise in profit shows its real marginal cost.

What this estimate deliberately leaves out

The model takes the standard deduction only and skips the QBI deduction, itemized deductions, credits, state estimated tax, and the 0.9% Additional Medicare Tax on high earners. The QBI omission means many freelancers' real bills come in somewhat lower than the estimate — a conservative direction for quarterly planning. If your situation has credits, dependents, or state obligations, treat this as the federal floor and confirm with a tax professional or software at filing time.

By variant

• Self-Employment Tax
• Safe-Harbor Payments

Questions

How much should I set aside for taxes as a freelancer?

At $90,000 of net profit filing single, the 2026 federal total is about $22,287.77 — roughly 25%. Lower profits skew the share down (SE tax dominates); add your state's income tax on top where applicable.

When are 2026 quarterly estimated taxes due?

Around April 15, June 15, and September 15, 2026, with the fourth payment due about January 15, 2027. Dates shift a day or two for weekends and holidays.

What happens if I skip a quarterly payment?

The IRS assesses an underpayment penalty that accrues like interest from each missed installment — even if you pay everything by the April filing deadline. The safe-harbor view shows the minimum that avoids it.

Do I owe quarterly taxes on a side gig if I also have a W-2 job?

Often yes, but your W-2 withholding counts toward the bill. A $25,000 side profit on top of an $80,000 salary with $9,000 withheld leaves about $8,413.83 to prepay — $2,103.46 per quarter. Raising W-2 withholding is a valid alternative to quarterly payments.

Is this tax advice?

No. It's the published 1040-ES arithmetic applied to your inputs with disclosed simplifications (standard deduction only, no QBI or credits). Confirm your actual obligations with a professional or filing software.