Freelance income in bursts: annualized installment calculator
Calculate the installment portion of the IRS annualized worksheet from your prepared tax figures, and see why uneven income can produce uneven payments.
Annualized installment calculator
Enter the four annualized tax amounts after credits from Publication 505 Worksheet 2-9, line 21, and your required annual payment from Worksheet 2-1, line 12c. This calculates lines 22–32; it does not compute your income tax, credits, or self-employment tax.
Jan–Mar
Jan–May
Jan–Aug
Jan–Dec
| Period | Required installment | Cumulative requirement | Remaining payment |
|---|---|---|---|
| Jan–Mar | $450 | $450 | $450 |
| Jan–May | $1,350 | $1,800 | $1,350 |
| Jan–Aug | $6,300 | $8,100 | $6,300 |
| Jan–Dec | $9,900 | $18,000 | $9,900 |
Payments are editable, not assumed paid. The default example has installments of $450, $1,350, $6,300, and $9,900. This is a federal planning worksheet, not a penalty calculation or filing service. It does not cover special farmer, fisher, estate, trust, or nonresident rules.
Use cumulative periods, not four equal quarters
The annualized method uses January–March, January–May, January–August, and January–December. The corresponding income annualization factors are 4, 2.4, 1.5, and 1. Income earned late in the year is not automatically treated as though it arrived in January.
This tool starts with the annualized tax after credits from Worksheet 2-9, line 21. Prepare those figures using the IRS worksheet or your tax adviser. Revenue alone is insufficient: deductions, self-employment tax, other taxes, and credits matter.
A worked late-income example
Assume line 21 is $2,000, $4,000, $12,000, and $20,000, and the required annual payment is $18,000. The calculator applies the worksheet’s percentage, prior-installment, and carryforward steps. Required installments are $450, $1,350, $6,300, and $9,900 before crediting payments and withholding.
This is a numerical worksheet example. It does not infer a particular freelancer’s income, deductions, or tax return. The result can be lower in early periods and higher later; annualization does not erase the year’s tax.
Separate a requirement from a payment
The required installment and the amount still to pay are different. Enter actual estimated payments already made before the installment and the withholding allocated through that due date. Do not include the proposed payment twice.
The calculator implements Worksheet 2-9 lines 22–32 with prepared inputs. It does not complete Form 2210, compute an underpayment penalty, determine relief eligibility, or apply state rules. Keep the underlying income and payment dates for filing.
Before relying on the result
Review the IRS instructions for withholding allocation and special situations. Farmers, fishers, nonresidents, estates, and trusts can have different rules. The IRS says taxpayers using the annualized method must file Form 2210 with the return.
Use the due-date guide for the relevant year and check disaster relief if it may apply. A planning calculation is not evidence that a payment reached the IRS.
Your checklist
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Sources and method
Sources reviewed September 12, 2026 unless a record carries its own observation date.