Maine Estimated Tax Payments 2026

Maine has two $1,000 tests, joined by “and”. The instructions say that in most cases you must pay estimated tax if your estimated Maine income tax for the year, over and above tax withheld and allowable credits, is $1,000 or more and if your tax liability for the prior year was also $1,000 or more. Read the full instructions if you think an exception applies to you, because the wording is “in most cases”.

• In most cases, you must pay estimated tax if your estimated Maine income tax for the year, over and above tax withheld and allowable credits, is $1,000 or more and if your tax liability for the prior year was also $1,000 or more.

  “In most cases, you must pay estimated tax if your estimated Maine income tax for the year, over and above tax withheld and allowable credits, is $1,000 or more and if your tax liability for the prior year was also $1,000 or more.”

• Certain taxpayers with large annual tax liabilities are required to remit tax payments electronically (the instructions point to Maine Rule 102 on the Maine Revenue Services website).

  “Certain taxpayers with large annual tax liabilities are required to remit tax payments electronically.”

The instructions say to use the worksheet on page 2 to calculate your estimated tax, and that to avoid penalties the estimated tax paid must be no less than the smaller of the following: (a) an amount equal to the preceding year’s tax liability, if the preceding year was a taxable year of 12 months; or (b) an amount equal to 90% of the tax liability for the current taxable year.

If you overpaid your 2025 income tax and elected to apply the overpayment to your 2026 estimated tax, the instructions say it may be partially or fully applied to any installment.

• To avoid penalties, the estimated tax paid must be no less than the smaller of the following: a) An amount equal to the preceding year’s tax liability, if the preceding year was a taxable year of 12 months; or b) An amount equal to 90% of the tax liability for the current taxable year.

  “To avoid penalties, the estimated tax paid must be no less than the smaller of the following: a) An amount equal to the preceding year’s tax liability, if the preceding year was a taxable year of 12 months; or b) An amount equal to 90% of the tax liability for the current taxable year.”

• If you overpaid your 2025 income tax and elected to apply the overpayment to your 2026 estimated tax, that overpayment may be partially or fully applied to any installment.

  “If you overpaid your 2025 income tax and elected to apply the overpayment to your 2026 estimated tax, that overpayment may be partially or fully applied to any installment.”

The instructions add a special rule for “unusual event income”. The rule, the two definitions it depends on and the extension and waiver provision are quoted below word for word. The rule applies only to income that meets those definitions, and the instructions say Maine income that is not unusual event income is subject to the regular estimated tax requirements. If you meet all of the listed criteria you are entitled to an extension of time to pay or a waiver of penalty, but the request must be submitted in writing to the State Tax Assessor and an extension may not run past the original due date for filing the return.

• Maine taxable income means income subject to Maine income tax, but which is not subject to Maine income tax withholding. For example, for purposes of this special rule, Maine taxable income includes business income and capital gains, but does not include wages.

  “Maine taxable income means income subject to Maine income tax, but which is not subject to Maine income tax withholding. For example, for purposes of this special rule, Maine taxable income includes business income and capital gains, but does not include wages.”

• Unusual event income means Maine taxable income (as defined above) received during an estimated tax installment period of the current tax year, but only if that amount exceeds the Maine taxable income received during the same estimated tax installment period of the prior tax year by $500,000 or more.

  “Unusual event income means Maine taxable income (as defined above) received during an estimated tax installment period of the current tax year, but only if that amount exceeds the Maine taxable income received during the same estimated tax installment period of the prior tax year by $500,000 or more.”

• Special Rule. If you have unusual event income, you must pay a Maine estimated tax on that income equal to 90% of the tax liability on that income. This special rule prohibits you from utilizing the prior year tax liability rule under paragraph a above to determine the amount of Maine estimated tax due on unusual event income. The estimated tax due on unusual event income is in addition to the estimated tax due on any other income received during the installment period (such as pension or annuity income subject to Maine income tax withholding where the Maine withholding amount is insufficient).

  “Special Rule. If you have unusual event income, you must pay a Maine estimated tax on that income equal to 90% of the tax liability on that income. This special rule prohibits you from utilizing the prior year tax liability rule under paragraph a above to determine the amount of Maine estimated tax due on unusual event income. The estimated tax due on unusual event income is in addition to the estimated tax due on any other income received during the installment period (such as pension or annuity income subject to Maine income tax withholding where the Maine withholding amount is insufficient).”

• Extension to pay; waiver of penalty. If you are subject to the special rule described above and you meet all of the criteria listed below, you are entitled to an extension of time to pay the estimated tax or to receive a waiver of penalty associated with the unusual event income. Any extension of time granted may not extend past the original due date for filing the return for the tax year. Requests for extension of time to pay or for waiver of penalty must be submitted to the State Tax Assessor in writing.

  “Extension to pay; waiver of penalty. If you are subject to the special rule described above and you meet all of the criteria listed below, you are entitled to an extension of time to pay the estimated tax or to receive a waiver of penalty associated with the unusual event income. Any extension of time granted may not extend past the original due date for filing the return for the tax year. Requests for extension of time to pay or for waiver of penalty must be submitted to the State Tax Assessor in writing.”

• a) You are an owner in a pass-through entity; b) You had no control over the distribution of the unusual event income; c) You did not actually or constructively receive payment of the unusual event income; and d) You pay the estimated tax on the unusual event income by the estimated tax installment payment due date following the installment period during which you actually or constructively receive the unusual event income.

  “a) You are an owner in a pass-through entity; b) You had no control over the distribution of the unusual event income; c) You did not actually or constructively receive payment of the unusual event income; and d) You pay the estimated tax on the unusual event income by the estimated tax installment payment due date following the installment period during which you actually or constructively receive the unusual event income.”

The first installment is due April 15, 2026. You may either pay all of your estimated tax at that time or pay in four equal installments on April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. If at least 2/3 of your estimated adjusted gross income is from farming or fishing, your estimated tax may be paid in a single installment due on or before January 15, 2027; if you file your 2026 individual income tax return on or before March 1, 2027, and pay the total tax at that time, you need not make an estimated tax payment.

If you are not required to pay on April 15, 2026 but your expected income changes so that you will be, the instructions say payment may be made at one time on the next installment due date or in equal installments on the remaining due dates, and that you should reduce the remaining installments if your estimated tax liability decreases because of an income change.

• The first installment payment is due on April 15, 2026. You may either pay all of your estimated tax at that time or pay in four equal installments on April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027.

  “The first installment payment is due on April 15, 2026. You may either pay all of your estimated tax at that time or pay in four equal installments on April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027.”

• If at least 2/3 of your estimated adjusted gross income is from farming or fishing, your estimated tax may be paid in a single installment due on or before January 15, 2027. If you file your 2026 individual income tax return on or before March 1, 2027, and pay the total tax at that time, you need not make an estimated tax payment.

  “If at least 2/3 of your estimated adjusted gross income is from farming or fishing, your estimated tax may be paid in a single installment due on or before January 15, 2027. If you file your 2026 individual income tax return on or before March 1, 2027, and pay the total tax at that time, you need not make an estimated tax payment.”

• If your estimated tax liability decreases because of an income change, reduce the remaining installments.

  “If your estimated tax liability decreases because of an income change, reduce the remaining installments.”

• If you report on a fiscal year basis, the dates should be changed to correspond with your fiscal year.

  “If you report on a fiscal year basis, the dates should be changed to correspond with your fiscal year.”

The instructions say to use the Maine Tax Portal (MTP) to pay estimated individual income tax electronically at revenue.maine.gov, and that electronic payments eliminate the necessity of filing Forms 1040ES-ME. To mail a payment, use the Form 1040ES-ME voucher for the installment (Voucher 1 due April 15, 2026, Voucher 2 June 15, 2026, Voucher 3 September 15, 2026, Voucher 4 January 15, 2027) and mail it with a check or money order payable to Treasurer, State of Maine, to Maine Revenue Services, P.O. Box 9101, Augusta, ME 04332-9101.

• Use the Maine Tax Portal (MTP) to pay estimated individual income tax electronically at revenue.maine.gov.

  “Use the Maine Tax Portal (MTP) to pay estimated individual income tax electronically at revenue.maine.gov.”

• Detach and mail this voucher with check or money order payable to Treasurer, State of Maine, to: Maine Revenue Services, P.O. Box 9101, Augusta, ME 04332-9101.

  “mail this voucher with check or money order payable to Treasurer, State of Maine, to: Maine Revenue Services, P.O. Box 9101, Augusta, ME 04332-9101.”

• If mailing the estimated income tax payment, Form 1040ES-ME may be downloaded at maine.gov/revenue/tax-return-forms.

  “If mailing the estimated income tax payment, Form 1040ES-ME may be downloaded at maine.gov/revenue/tax-return-forms.”

• Maine Revenue Services’ 2026 individual income tax forms page lists 1040ES-ME (revised July 2026), Estimated Payment Vouchers, with the Maine Tax Portal as its instructions link.

  “1040ES-ME (PDF) - Revised July 2026 Estimated Payment Vouchers Maine Tax Portal”

Official page: Maine Tax Portal (revenue.maine.gov): pay estimated individual income tax. Form: Form 1040ES-ME (Estimated Tax Payment Vouchers for Individuals).

Item 6 of the instructions says a penalty accrues automatically on underpayments of the required installment amount for the period of underpayment, and that it does not apply if each required payment was made on time and the total estimated tax paid equals 90% (66 2/3% for farmers and fishermen) of the current year’s income tax liability or 100% of the preceding year’s, if that year was a taxable year of 12 months. The forms page lists Form 2210ME, Underpayment of Estimated Tax Penalty Calculation. This page does not state a penalty rate because the instructions do not.

• A penalty accrues automatically on underpayments of the required installment amount for the period of underpayment. The penalty does not apply if each required payment was made on time and if the total estimated tax paid is equal to 90% (66 2/3% for farmers and fishermen) of the income tax liability for the current year or 100% of the tax liability for the preceding year, if that year was a taxable year of 12 months.

  “A penalty accrues automatically on underpayments of the required installment amount for the period of underpayment. The penalty does not apply if each required payment was made on time and if the total estimated tax paid is equal to 90% (66 2/3% for farmers and fishermen) of the income tax liability for the current year or 100% of the tax liability for the preceding year, if that year was a taxable year of 12 months.”

• Maine Revenue Services’ forms page lists Form 2210ME, Underpayment of Estimated Tax Penalty Calculation.

  “Form 2210ME (PDF) Underpayment of Estimated Tax Penalty Calculation”