FT

Freelance Finance

Quarterly Tax Estimator

Plan estimated tax payments using expected annual tax, withholding, credits, and the IRS safe-harbor rules.

Filing status Used for the higher-income 110% safe-harbor rule.
Estimated federal tax ($)

Your projected full-year federal income and self-employment tax.

Estimated state tax ($)

Optional state estimate to include in your cash planning.

Expected withholding ($)

W-2 withholding, retirement withholding, or other tax already being withheld.

Refundable credits ($)

Credits that directly reduce tax still due.

Prior-year total tax ($)

Use the total tax from last year's return. Enter 0 if you had no prior-year tax liability.

Prior-year AGI ($)

Used to decide whether the 110% safe harbor applies.

Estimated payments already made ($)

Any quarterly payments you have already sent this year.

Payments remaining

Used to spread the remaining amount across upcoming due dates.

How the target is chosen

Projected balance due
$22,000.00
90% of current-year tax
$19,800.00
Prior-year safe harbor (100%)
$18,000.00

Safe-harbor payment

$4,500.00

Per remaining payment based on the smaller of the two federal safe-harbor targets.

Breakdown

Required annual payment
$18,000.00
Payments already made
$0.00
Safe-harbor balance left
$18,000.00
Full projected tax left
$22,000.00
Full-pay amount per remaining payment
$5,500.00

Standard due dates

Q1
April 15
Q2
June 15
Q3
September 15
Q4
January 15

How quarterly estimated taxes are planned

The IRS pay-as-you-go system generally expects you to pay enough tax during the year through withholding or estimated payments. Most taxpayers avoid the federal underpayment penalty if total prepayments reach the smaller of 90% of current-year tax or 100% of prior-year tax. For higher-income taxpayers, the prior-year benchmark rises to 110%.

The formulas

total_estimated_tax     = estimated_federal_tax + estimated_state_tax
prepayments             = expected_withholding + refundable_credits
projected_balance_due   = max(0, total_estimated_tax - prepayments)

current_year_target     = max(0, 0.90 * total_estimated_tax - prepayments)
safe_harbor_target      = max(0, prior_year_total_tax * safe_harbor_percent - prepayments)
required_annual_payment = min(current_year_target, safe_harbor_target)

safe_harbor_balance     = max(0, required_annual_payment - payments_already_made)
recommended_payment     = safe_harbor_balance / payments_remaining

What this tool does and does not do

This is a payment planner, not a full tax-prep engine. You enter your own projected annual tax so you can compare a penalty-safe minimum against the higher amount needed to fully cover your projected tax bill. It does not compute federal brackets, QBI, AMT, or state-specific tax law for you.

Important notes

If your income is uneven during the year, the annualized installment method may produce a lower required payment than equal quarterly installments. Farmers, fishers, and certain other taxpayers have special rules. State estimated-tax rules also vary, so use the state amount here as a planning number rather than a legal state filing calculation.

FAQ

Does withholding count the same as quarterly payments?

For planning purposes, yes. Withholding reduces the remaining amount you need to send with estimated payments.

What if my prior-year tax was zero?

Many taxpayers qualify for the no-prior-year-tax exception if last year was a full 12-month U.S. return with zero tax liability.

Why show a full-pay amount and a safe-harbor amount?

The safe-harbor amount is about penalty avoidance. The full-pay amount is about fully covering the tax you expect to owe.