State estimated tax — 2026

Indiana Estimated Tax Payments 2026

Who has to make Indiana quarterly estimated payments, the 2026 due-date calendar, the safe-harbor rules that avoid an underpayment penalty, and how to pay through INTIME.

Who must pay

Indiana requires Form ES-40 payments once your total unpaid state AND county income tax liability for 2026 — combined, not state alone — will be $1,000 or more, on income Indiana withholding doesn’t already cover.

2026 due-date calendar

Installment	% of annual estimate	Due date	Note
Q1	25%	April 15, 2026	—
Q2	25%	June 15, 2026	—
Q3	25%	September 15, 2026	—
Q4	25%	January 15, 2027	—

Indiana divides the required annual payment by four for equal 25% installments. If a due date falls on a Saturday, Sunday, or a legal holiday the IRS recognizes for federal estimated-tax purposes, Indiana treats a payment postmarked the next business day as timely. Farmers and fishermen (at least two-thirds of gross income from farming or fishing) owe no penalty if they file Form IT-40 or IT-40PNR and pay their full tax by March 1 — note this is a full exemption from the installment schedule, not a reduced safe-harbor percentage the way most other states handle farmers. Anyone can also avoid a penalty on just the fourth installment by filing their return and paying the full balance by January 31.

Safe harbor — avoiding the underpayment penalty

Indiana pegs your required annual payment to whichever number comes out smaller: 90% of what 2026 actually costs you, or the full total from your 2025 return. Non-farmers and non-fishermen whose 2025 federal AGI cleared $150,000 ($75,000 filing separately) lose the round-number version of that second option — theirs is bumped to 110% instead. Miss a quarter and Schedule IT-2210 charges a flat 10% of that period’s shortfall, a fixed multiplier rather than the accruing daily-interest formula most neighboring states use.

How to calculate your payment

Estimate your annual Indiana tax, test it against the safe harbor above, then split the required annual payment across the installments in the calendar. The site's quarterly planner handles the math and the federal side together.

Open the quarterly estimated tax calculator → Check your underpayment penalty exposure →

How to pay

Pay online through INTIME, or mail a check or money order with the Form ES-40 voucher.

Penalty basics

Indiana’s underpayment penalty is a flat 10% of the shortfall for each period (Income Tax Information Bulletin #3, IC 6-3-4-4.1) rather than an accruing daily-interest calculation. Separately, Indiana charges interest on any unpaid tax balance at a rate the Department sets annually under IC 6-8.1-10-1 — 7% for calendar year 2026 (Departmental Notice #3), up from 6% in 2025.

Indiana-specific notes

County income tax (LIT) rides on the SAME ES-40 voucher as state tax — Indiana sums both into one “Total Estimated Income Tax” figure, and the $1,000 threshold and required-annual-payment math are both based on the combined state-plus-county total, not state tax alone. Misallocating between the state and county lines on the worksheet doesn’t itself trigger a penalty.
Indiana’s state flat rate is still phasing down: 2.95% for 2026 (from 3.0% in 2025), scheduled to fall again to 2.90% in 2027.
County rates vary widely — as low as 0.5% (Porter County) and as high as 3.0% (Randolph County) on the January 1, 2026 rate table — and the Department reissues the county rate chart (Departmental Notice #1) twice a year, in January and October, flagging any county whose rate changed since the last edition.
Spouses filing a joint Indiana return who live in different counties must compute each spouse’s county tax separately using their own county’s rate, even though the state tax is combined.

See the Indiana 2026 tax brackets for current rates, or the Indiana state tax calculator to estimate your full-year liability.

Frequently asked questions

When are Indiana estimated tax payments due in 2026?

The four Indiana due dates for 2026 are April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Indiana divides the required annual payment by four for equal 25% installments. If a due date falls on a Saturday, Sunday, or a legal holiday the IRS recognizes for federal estimated-tax purposes, Indiana treats a payment postmarked the next business day as timely. Farmers and fishermen (at least two-thirds of gross income from farming or fishing) owe no penalty if they file Form IT-40 or IT-40PNR and pay their full tax by March 1 — note this is a full exemption from the installment schedule, not a reduced safe-harbor percentage the way most other states handle farmers. Anyone can also avoid a penalty on just the fourth installment by filing their return and paying the full balance by January 31.

Does my Indiana estimated tax payment need to cover county tax separately?

No — it’s combined. Indiana’s ES-40 worksheet adds your state tax and county (LIT) tax into a single “Total Estimated Income Tax” figure that you pay in one combined installment, and the $1,000 threshold that triggers the requirement is based on that combined total, not state tax alone.

How do I know what my Indiana county tax rate is for estimated-tax purposes?

Check Indiana DOR’s Departmental Notice #1, reissued every January 1 and October 1 with a full county-by-county rate table. Rates ranged from 0.5% in Porter County to 3.0% in Randolph County on the January 2026 edition, and six counties changed rates for that release alone — don’t assume last year’s rate still applies.

Does Indiana have a special rule for farmers and fishermen?

Yes, but it’s structured differently than most states: instead of a reduced safe-harbor percentage, Indiana farmers and fishermen (at least two-thirds of gross income from farming or fishing) owe no underpayment penalty at all if they file their return and pay their full tax by March 1.

How do I pay Indiana estimated tax?

Pay online through INTIME, or mail a check with the Form ES-40 voucher.

Estimated tax in other states

Compare how Indiana stacks up against the other states with a Rising search trend for estimated-tax rules.