How to Calculate Your Estimated Quarterly Tax: A Guide

What estimated tax is

Most workers never think about estimated tax: their employer withholds it from every paycheck. Freelancers, landlords, and side-hustle earners have no employer doing that, so the IRS makes them pay as they go — four payments a year, due April 15, June 15, September 15, and January 15. The calculation is four steps: taxable income, the tax, credits and withholding, and divide by four.

Step 1: Work out your taxable income

Taxable income is your income minus your deductions, floored at zero. On $80,000 of income with the $16,100 standard deduction for a single filer, taxable income is $63,900.00. The 2026 standard deductions: $16,100 single, $32,200 married filing jointly, $24,150 head of household, $16,100 married filing separately. Itemizing $25,000 instead cuts taxable income to $55,000.00 and the tax to $6,812.00. With no deductions at all, taxable income is the full $80,000.00 and the tax is $12,312.00.

Step 2: Work out the tax from the brackets

The 2026 federal brackets (IRS Revenue Procedure 2025-32) tax your income in slices: for a single filer, 10% on the first $12,400, 12% up to $50,400, 22% up to $105,700, 24% up to $201,775, 32% up to $256,225, 35% up to $640,600, and 37% above that. On $63,900.00 of taxable income the tax is $1,240.00 + $4,560.00 + $2,970.00 = $8,770.00. The marginal rate — the rate on your last dollar — is 22%. The effective rate — the average across all your dollars — is $8,770.00 ÷ $63,900.00 = 13.72%.

Step 3: Subtract credits and withholding

Credits come straight off the tax bill, dollar for dollar — unlike deductions, which only shrink the income the brackets see. A $2,000 credit cuts the $8,770.00 bill to $6,770.00, and the quarterly payment to $1,692.50. A $10,000 credit wipes the bill out: the tax after credits is $0.00 and the quarterly payment is $0.00 — credits cannot make the bill negative. Then subtract anything already withheld: with $4,000 withheld, the amount still owed is $4,770.00 and the quarterly payment is $1,192.50. With $8,770 withheld the amount owed is $0.00.

Step 4: Divide by four

The quarterly payment is the amount owed divided by four. On $8,770.00 owed, each quarterly payment is $2,192.50. At $50,000 of income: tax $3,820.00, quarterly $955.00. At $120,000: $17,570.00 and $4,392.50. At $200,000: $36,734.00 and $9,183.50. At $1,000,000: $320,000.25 and $80,000.06.

The safe harbor: the cheapest way to dodge the penalty

Pay too little and the IRS charges an underpayment penalty — unless you meet the safe harbor. It lets you pay last year’s bill instead of this year’s: at least the smaller of 90% of this year’s tax or 100% of last year’s tax — 110% of last year’s tax when this year’s income is over $150,000. With $10,000 of prior-year tax, the safe-harbor quarterly payment is $2,500.00 — but the current-year quarterly payment of $2,192.50 is smaller, so the recommended payment stays $2,192.50. With $7,000 of prior-year tax, the safe-harbor quarterly payment is $1,750.00, so the recommended payment is $1,750.00. Paying the safe harbor dodges the penalty even though the real bill is higher; you true up at filing. With $30,000 of prior-year tax at $200,000 of income, the safe harbor is 110% of last year’s tax: $33,000.00 a year, $8,250.00 a quarter — smaller than $9,183.50, so the recommended payment is $8,250.00.

The worked example

Take a single filer earning $80,000, with the $16,100 standard deduction, no credits, nothing withheld, and no prior-year tax. Step 1: taxable income is $80,000 − $16,100 = $63,900.00. Step 2: the tax is $1,240.00 + $4,560.00 + $2,970.00 = $8,770.00; the marginal rate is 22% and the effective rate is 13.72%. Step 3: no credits and nothing withheld, so the amount owed is $8,770.00. Step 4: the quarterly payment is $8,770.00 ÷ 4 = $2,192.50. With no prior-year tax entered there is no safe harbor, so the recommended quarterly payment is $2,192.50. Rounding convention: totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum.

Working backwards

Sometimes you want the income that goes with a payment. The income for a $2,500 quarterly payment — $10,000 of tax — is $85,590.91 (exact 85590.9091); at $85,590.90 the unrounded tax is $9,999.9980, which also rounds to $10,000.00 — the exact value decides. The income for a $1,000 quarterly payment is $51,500.00; at $51,500 the tax is $4,000.00 exactly. The income for $0 tax is $16,100.00 — the standard deduction; at $16,100 the tax is $0.00, at $16,101 it is $0.10. The credits for $0 owed are $8,770.00; the withholding for $0 owed is also $8,770.00. The prior-year tax for a $2,000 safe-harbor quarterly is $8,000.00. The income for a $5,000 quarterly payment is $130,275.00; at $130,275 the tax is $20,000.00 exactly.

What changes the answer most

Your income moves the answer most: $50,000 gives a $955.00 quarterly payment; $80,000 gives $2,192.50; $120,000 gives $4,392.50; $200,000 gives $9,183.50; $1,000,000 gives $80,000.06. Your deductions are third: itemizing $25,000 instead of the $16,100 standard deduction saves $1,958.00 of tax at $80,000 of income. Credits and withholding change only what you still owe, never the tax itself: a $2,000 credit cuts the quarterly payment from $2,192.50 to $1,692.50, and $4,000 withheld cuts it to $1,192.50.

What not to do

Do not skip a payment — the penalty is charged on the shortfall for each quarter, from the due date. Do not confuse the marginal rate with the effective rate: at $80,000 of income your top dollars are taxed at 22%, but your average rate is only 13.72%. Do not assume the safe harbor is always cheaper: with $10,000 of prior-year tax it is $2,500.00 a quarter, more than the current-year payment of $2,192.50. And do not forget the fourth payment: it is due January 15, 2027.

How this connects

To run your own numbers, use the estimated quarterly tax calculator. For the bracket detail, see the 2026 federal tax brackets, and to see what the same income leaves after tax, see the take-home pay calculator.