Delaware · reference

Delaware calendar and forms

Every Delaware date that matters for the 2026 return, from the last estimated payment in January 2027 to the extended due date in October, and a plain-English guide to the forms an ordinary Delaware filer will meet. With the one date that trips people up every year: the return is due April 30, not April 15, and the federal extension does not cover it.

By Charles Trautman, EA, editor

Need to Know Tax · written from Delaware Division of Revenue sources, November 3, 2026; updated November 12, 2026 after the election · not yet reviewed by a Delaware practitioner

Delaware runs its own calendar. The resident return, Form PIT-RES, is due Friday, April 30, 2027, fifteen days after the federal return, and the first 2027 estimated payment is due the same day. The federal extension does not extend the Delaware return; to get to October 15, 2027, you file Form PIT-EXT or request the extension on the Delaware Taxpayer Portal by April 30, and you pay what you expect to owe at the same time, because there is no extension of time to pay. Interest runs at half a percent a month from April 30 on anything unpaid. Everything else is simpler than it looks: one return for residents, one for nonresidents, a Delaware Schedule A for people who itemize, and a handful of schedules that attach only when they apply.

The form names changed a few years ago from numbers to letters, which is why an old return says Form 200-01 and a new one says PIT-RES (verify). They are the same return. All current forms are on the Division of Revenue’s Personal Income Tax Forms page, and the Delaware Taxpayer Portal files PIT-RES and PIT-NON free, with no income limit, for anyone willing to type the figures in.

The 2027 filing season, dated

Delaware dates for the 2026 return and 2027 payments
Date	What happens	Form
Friday, January 15, 2027	Fourth and final 2026 estimated payment due.	PIT-EST
Late January 2027; the IRS announces the date in January	The Division begins accepting 2026 returns, on or near the day the IRS opens. The Portal opens the same day.	PIT-RES, PIT-NON
Mid-February 2027 (verify)	Earliest refunds. The Division held 2025 refunds until February 16, 2026, to screen for identity theft; expect the same pattern.
Friday, April 30, 2027	PIT-RES and PIT-NON due, and all 2026 tax due. Last day to file PIT-EXT. First 2027 estimated payment due.	PIT-RES, PIT-NON, PIT-EXT, PIT-EST
Tuesday, June 15, 2027	Second 2027 estimated payment due.	PIT-EST
Wednesday, September 15, 2027	Third 2027 estimated payment due.	PIT-EST
Friday, October 15, 2027	Extended due date for the 2026 return. Any balance still unpaid has drawn interest since April 30.	PIT-RES, PIT-NON
January 2028	Fourth 2027 estimated payment. January 15, 2028 is a Saturday; expect the next business day.	PIT-EST
Tuesday, April 30, 2030	Last day to amend the 2026 return for a refund: three years from the original due date, or two years from the date the tax was paid, whichever is later.	PIT-RES, amended box
A federal change to your 2026 return, from an audit or an amended 1040, must be reported to Delaware within 90 days of the final federal determination. County property tax bills and the Senior School Property Tax Credit run on county calendars, not the Division’s; the credit is claimed at the county, not on PIT-RES (verify the county deadlines).

How the extension really works

Delaware does not grant an automatic extension and does not accept the federal Form 4868 in place of its own. You request it, on Form PIT-EXT by mail or on the Delaware Taxpayer Portal, on or before April 30, and the return is then due October 15. Each return needs its own request; the Division grants no blanket extensions. The form asks for your expected tax, your withholding and estimated payments, and the balance, which is meant to be paid with it. Interest at one-half of one percent a month runs from April 30 on any tax not paid by then, and the Division’s FAQ adds a late-payment penalty of 1% a month, up to 25%. A return filed late with no extension and a balance due draws 5% a month on top. So: file PIT-EXT with a check, or pay on the Portal and request the extension there, by April 30. Too high an estimate comes back as a refund; too low, and interest runs only on the shortfall.

Estimated payments

Delaware requires estimated payments when the tax for the year, after withholding, can reasonably be expected to exceed $800. Pay at least 90% of this year’s tax or 100% of last year’s in four timely installments and there is no penalty; the prior-year figure rises to 110% if last year’s federal AGI was over $150,000 ($75,000 married filing separately). The penalty for a late or short installment is 1.5% a month, figured on Form PIT-UND, and it is waived when the shortfall is $800 or less. The first installment is due April 30, with the return, not April 15. The people most often caught are not retirees but the self-employed, owners of partnerships and S corporations, anyone with a large capital gain or Roth conversion, and new arrivals whose out-of-state employer does not withhold Delaware tax. Nonresidents who sell Delaware real estate have tax withheld at closing on Form REW-EST, which counts as a payment.

The forms, in the order a filer meets them

Delaware individual income tax forms, tax year 2026 (2025 versions linked until the 2026 forms post)
Form	What it does	Who needs it
PIT-RES	The resident return. Federal AGI on line 1, Delaware additions and subtractions including the pension exclusion and the Social Security subtraction, the standard or itemized deduction, the tax, the $110 credits, the EITC on Schedule II, withholding and payments. Also the amended return: check the box.	Every full-year resident; part-year residents who choose it
PIT-RSA	Delaware Schedule A. Federal itemized deductions rebuilt for Delaware: medical over 7.5% of AGI, taxes paid with state income tax counted only to the extent not claimed as a credit and the $40,000 SALT cap on line 5f, mortgage interest, charity. Can be used even if you took the federal standard deduction.	Anyone whose Delaware itemized deductions beat $3,250 / $6,500
PIT-NON	The nonresident return, with Delaware-source and total-income columns. Part-year residents may file it instead of PIT-RES and prorate; file whichever gives the lower tax. The EITC, child care credit and firefighter credit cannot be claimed on it.	Nonresidents with any Delaware-source income; part-year residents who choose it
PIT-SCW, Schedule W	Apportions a nonresident’s wages by days worked in and out of Delaware. Out-of-state days count only when the work outside Delaware was required by the employer, listed day by day with location and purpose; working from home for your own convenience does not qualify.	Nonresidents paid by a Delaware employer who worked some days elsewhere
PIT-EST	Estimated tax vouchers and the worksheet, which also prints the current rate schedule, standard deduction and $110 credit. Payments can be made on the Portal without the voucher.	Anyone expecting to owe more than $800 after withholding
PIT-EXT	Application for extension of time to file, to October 15. Due April 30 with the expected balance. Not automatic, and the federal extension does not substitute for it.	Anyone who will file after April 30
PIT-UND	Underpayment of estimated tax. Figures the 1.5%-a-month penalty by installment, with the annualized-income method and the farmer and fisherman exception.	Anyone who owed more than $800 and missed or shorted an installment
PIT-CRS	Income tax credit schedule for the credits with their own rules: the other-state credit, volunteer firefighter credit, and the business credits such as research and development, historic preservation and Neighborhood Assistance.	Commuters, volunteer firefighters, business owners with Delaware credits
PIT-STC	Special tax computation for a lump-sum distribution from a qualified retirement plan, taxed separately from the rest of the return.	The rare filer who took a lump sum and used the federal ten-year averaging
REW-EST	Real estate withholding and estimated tax declaration. Delaware tax withheld at closing when a nonresident sells Delaware property; the withholding is claimed as a payment on PIT-NON.	Nonresident sellers of Delaware real estate
For withholding, Delaware accepts the federal Form W-4 for the state certificate (verify whether a separate Delaware W-4 is also published). Wilmington’s earned income tax is filed with the city on the city’s own form, not with the Division.

Filing, paying and checking a refund

The Division says an e-filed return that needs no further review can be refunded “in as little as 10 days,” while paper returns and returns pulled for review average about twelve weeks. No refund goes out before mid-February regardless of when the return is filed. The Delaware Taxpayer Portal, at tax.delaware.gov, is the Division’s own system: it files the current-year and prior-year PIT-RES and PIT-NON free of charge with no income limit, takes payments and estimated payments by bank debit, files the extension request, and runs “Check the Status of Your Refund,” which asks for your Social Security number and the exact refund amount. It does not file the federal return. Commercial software and preparers e-file the Delaware return together with the federal one. Delaware was not an IRS Direct File state for the 2026 season.

Paper returns go to one of three post office boxes in Wilmington, depending on whether the return shows a balance due (P.O. Box 508), a refund (P.O. Box 8710) or neither (P.O. Box 8711) (verify the ZIP+4 codes on the current instructions); PIT-EXT goes to P.O. Box 830. The Division warns that it does not send text messages about refunds, so a text asking for bank details is not from them.

How to reach the Division

Personal income tax assistance is at (302) 577-8200, or (800) 292-7826 toll-free inside Delaware, with public service counters open Monday through Friday from 8:00 to 4:00 at the Carvel State Office Building, 820 North French Street, Wilmington; the Thomas Collins Building, 540 South DuPont Highway, Dover; and 20653 DuPont Boulevard, Suite 2, Georgetown. Refund questions go to (302) 577-8784; collections and payment plans to (302) 577-8785; the Portal help desk by email at TaxPortal@delaware.gov. The Division’s general email for personal income tax is DOR_PublicService@delaware.gov.

Worked example: a balance due and a late return

A self-employed filer in Kent County expects to owe $2,400 of Delaware tax for 2026 after withholding, and the books will not be closed by April 30. Three paths, all ending with the return filed on October 1, 2027.

	PIT-EXT with $2,400 by April 30	PIT-EXT by April 30, pays in October	No extension, files and pays in October
Paid April 30, 2027	$2,400	$0	$0
Interest, 0.5% a month, May through October (6 months)	$0	$72	$72
Late-payment penalty, 1% a month	$0	$144	$144
Late-filing penalty, 5% a month on the balance	$0	$0	$720
Paid in total	$2,400	$2,616	$3,336

The $2,400 is the same in every column. The extension request, which takes two minutes on the Portal, is worth $720 by itself; the payment with it is worth another $216. Delaware counts a fraction of a month as a month, so the counts above are approximate and the Division’s bill may differ by a month.

Behind the scenes: why the April 30 date cuts both ways

Delaware’s statute sets the individual return due on the last day of the fourth month after the year ends, which for a calendar-year filer is April 30, and the estimated-payment calendar is built around it: the first installment comes with the return on April 30, and the other three fall on the federal dates. The extra two weeks help anyone whose Delaware return depends on a finished federal return. The cost is that national software and national habits run on April 15. A Delaware filer who files federally on time and forgets the state is rarely late, while one who files a federal extension and assumes it covers Delaware is late by definition. The Delaware extension form doubles as the payment voucher, which is the practical reason the Division wants its own request rather than a copy of Form 4868: the state collects the balance with the request.

What to bring

Every W-2 and 1099 showing Delaware withholding
The 2026 estimated payments made, with dates and amounts; the Portal can list them
Last year’s PIT-RES, for the 100% safe harbor and any carryovers
The other state’s return, signed, if you are claiming the credit for tax paid elsewhere
Property tax, mortgage interest and charitable figures, to test PIT-RSA against the standard deduction
The closing statement and Form REW-EST if you sold Delaware real estate as a nonresident
Any letter from the Division, and your bank routing and account numbers for direct deposit

Questions people ask

When is the Delaware return due?

April 30, 2027, for the 2026 return. Fifteen days after the federal return. The first 2027 estimated payment is due the same day.

I filed a federal extension. Am I covered in Delaware?

No. Delaware requires its own request, Form PIT-EXT or the extension on the Delaware Taxpayer Portal, by April 30. With it, the return is due October 15. Without it, a return filed in May is late and a balance due draws the 5%-a-month penalty.

Does the extension give me more time to pay?

No. Interest at 0.5% a month and a late-payment penalty run from April 30 on any unpaid tax, extension or not. Send the expected balance with PIT-EXT or pay it on the Portal.

Can I file my Delaware return for free?

Yes. The Delaware Taxpayer Portal files PIT-RES and PIT-NON at no charge with no income limit. It does not file the federal return, so most people use it after finishing the 1040 elsewhere, or let their software or preparer e-file both together.

How long will my refund take?

As little as ten days for an e-filed return that needs no review, about twelve weeks on paper, and nothing before mid-February. “Check the Status of Your Refund” on the Portal shows where it stands.

Do I need to make estimated payments?

If your Delaware tax after withholding will be more than $800, yes: four installments on April 30, June 15, September 15 and January 15, or enough withholding to reach 90% of this year’s tax or 100% of last year’s (110% above $150,000 of AGI). The penalty is 1.5% a month on the shortfall.

How do I fix a Delaware return I already filed?

File another PIT-RES with the amended box checked, within three years of the original due date or two years of payment for a refund. If the IRS changed your federal return, report it to Delaware within 90 days of the final determination and attach the federal adjustments.

April 30, not April 15, and Delaware’s own extension or none

Put April 30 on the calendar for both the return and the first estimate, request PIT-EXT with a payment if the return will be late, and use the Portal to check that every payment landed.

Written by Charles Trautman, EA, editor  ·  Need to Know Tax, Lone Tree, Colorado
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Updated November 12, 2026, after the November 3 election · tax year 2026 figures · awaiting review by a Delaware practitioner — use the right article