Frequently Asked Questions

Our calculations use the official IRS methods, safe harbor and annualized income, straight from Publication 505. The calculator is built with experienced CPAs and uses current tax brackets, rates, and thresholds.

The safe harbor method bases your payments on last year's total tax. Pay 100% of it (110% for higher incomes) in equal installments and you are protected from underpayment penalties no matter what you earn this year. The annualized income method bases each payment on what you have actually earned so far this year, which can mean lower payments when income is irregular. The calculator computes both and shows which works out lower.

The quick check on the homepage works without an account. The full calculator needs a free account so your numbers can be saved. Signing up takes an email address only. We send a 6-digit code to sign you in, so there is no password to manage.

The free plan gives you the complete payment number, federal plus your state safe harbor figure, along with deadline reminders. Paid plans add year-round tools like the quarterly PDF report and saved history, and multi-client management for tax professionals. The pricing page has the current comparison.

The calculator supports W-2 wages, self-employment income, partnership and S-Corp distributions, rental income, investment income (dividends, capital gains), and other miscellaneous income. It also handles passive activity income and loss limitations.

The calculator applies IRS passive activity loss rules, including the $25,000 allowance for real estate activities (subject to income phase-outs) and proper treatment of passive vs. non-passive income and losses.

The calculator is designed for individual quarterly estimated tax payments. It handles business income from sole proprietorships, partnerships, and S-Corps that flows through to personal returns, but not separate business entity taxes.

For states with an income tax, the calculator shows your state safe harbor payment estimate alongside the full federal calculation. The detailed annualized method is federal only.

You only need to calculate once per quarter using your year-to-date net income as of the quarter closing date (March 31, May 31, August 31, or December 31).

Yes, you can calculate payments for any quarter. The calculator will account for payments already made and determine the remaining amount needed for the selected quarter.

Yes. You can email your quarterly estimates to your accountant straight from the app on any plan. Paid plans attach the full PDF report, and the free plan sends the summary numbers.

Your data is stored securely and never sold. Social Security numbers are never stored at all. When you generate a payment voucher, we ask for the SSN at that moment, place it on the PDF, and discard it.

EstimatedTax.com provides calculation tools and educational information but does not constitute professional tax advice. For complex situations or specific tax guidance, consult with a qualified tax professional.

The calculator uses the current tax year's brackets, rates, and thresholds. We update them each year when the IRS publishes new figures.

Pay the missed amount as soon as you can instead of waiting for the next deadline. Interest builds daily on the shortfall from its due date, and a payment stops the clock the day it arrives. The calculator accounts for payments already made and figures the catch-up amount for the quarter you select.

• What happens if I missed a quarterly payment?
• The Underpayment Penalty

The Learn section has plain-language guides to the safe harbor rule, the annualized income method, due dates, and the underpayment penalty, plus guides for situations like your first year of self-employment or a one-time windfall. The Calculators section has free standalone calculators for specific questions.