Does Idaho Accept a Federal Tax Extension?

Tax extensions offer individuals more time to prepare and submit income tax returns. While a federal extension grants additional time with the IRS, taxpayers must also understand their state’s specific requirements. Each state has its own rules regarding tax extensions, including whether it automatically accepts a federal extension or requires a separate state application. This understanding is essential for avoiding penalties and ensuring compliance with state tax laws.

Idaho’s Acceptance of Federal Tax Extensions

Idaho does not automatically accept a federal tax extension (Form 4868) for state income tax filing. Instead, Idaho provides its own automatic six-month extension for individual income tax returns, shifting the filing deadline from April 15 to October 15 for calendar year filers. This automatic extension is granted without needing to file a separate form with the Idaho State Tax Commission, provided certain payment conditions are met.

To qualify, taxpayers must pay at least 80% of their estimated Idaho tax liability for the current year by the original April 15 deadline. Alternatively, they can qualify by paying 100% of the total tax reported on their previous year’s Idaho income tax return, assuming a return was filed for that year. Meeting these payment thresholds avoids a penalty for filing late. However, this extension is solely for filing the return and does not extend the time to pay any tax due.

Requesting an Idaho-Only Extension

An Idaho-only extension is an automatic extension granted if specific payment criteria are satisfied. Taxpayers do not need to file a distinct extension form, such as Form 51, if they meet the payment requirements by the original April 15 deadline. Form 51, titled “Estimated Payment of Individual Income Tax,” primarily serves as a payment voucher for estimated taxes or for making a payment to qualify for the automatic extension.

To determine if a payment is necessary, taxpayers can use the worksheet provided on Idaho Form 51. This worksheet helps calculate the estimated tax liability and any remaining amount due after accounting for withholdings and previous payments. If a payment is needed to meet the 80% or 100% threshold, taxpayers will complete Form 51 with their personal details, estimated tax liability, and the payment amount. The official Form 51 can be found on the Idaho State Tax Commission website.

Once completed, Form 51, along with the payment, can be submitted by mail to the address provided on the form. Alternatively, taxpayers can make an online payment through the Idaho State Tax Commission’s E-Pay system, often using a “Quick Pay” service that does not require an account. This online payment method negates the need to mail Form 51 itself, as the payment indicates the intention to extend. If no payment is due or if the payment needed is $50 or less, mailing Form 51 is not required to obtain the extension.

Payment Responsibilities with an Extension

An extension of time to file an income tax return does not extend the time to pay any taxes owed. All tax liabilities must be paid by the original April 15 due date to avoid penalties and interest. If the tax due is not paid by this date, interest will accrue on the unpaid balance from the original due date until the payment date. The annual interest rate is 6% on any tax owed after April 15.

Penalties may also apply if sufficient tax is not paid by the original deadline, even with a valid extension to file. A late payment penalty, often 0.5% per month, can be assessed on the unpaid balance. Additionally, a late filing penalty, usually 5% per month up to 25% of the unpaid tax, applies if the return is filed after the extended due date or if the conditions for the automatic extension were not met. To avoid these charges, taxpayers should make estimated payments or pay their full tax liability by April 15, using options such as the Idaho State Tax Commission’s QuickPay online service or by mailing a check with Form 51.