There are 3 changes effective 7/1/25.

California changed to 7% for underpayments and 4% for overpayments.

Michigan changed to 8.66% for both underpayments and overpayments.

Tennessee changed to 11.50% for both underpayments and overpayments.

There are only 2 changes for this release.

The following rate change became effective January 1, 2025. As noted with release 25.1.0.0, not all jurisdictions had published their rates for the first quarter of 2025 when that release was posted. The following change has been added:

Maryland changed to 11.4825% for their underpayment and overpayment rate.

The following correction was made:

For Missouri, for the 1st quarter of 2025, the underpayment rate was corrected to be 8.000% from 9.000%.

The following rate changes became effective January 1, 2025. As noted with release 25.1.0.0, not all jurisdictions had published their rates for the first quarter of 2025 when that release was posted. The following changes have been added:

• Texas changed from 4.981% to 4.597% for overpayments.

The following jurisdiction published new changes that went into effect on January 1, 2025:

• Alaska changed from 10.25% to 9.75% for both underpayments and overpayments.
• Alabama changed from 8.00% to 7.00% for both underpayments and overpayments.
• Arizona changed from 8.00% to 7.00% for both underpayments and overpayments.
• Federal changed from 8.00% to 7.00% for underpayments and from 7.00% to 6.00% on overpayments.
• Georgia changed from 11.50% to 10.50% for both underpayments and overpayments.
• Illinois changed from 8.00% to 7.00% for both underpayments and overpayments.
• Indiana changed from 4.00% to 6.00% for both underpayments and overpayments.
• Kansas changed from 8.00% to 9.00% for both underpayments and overpayments.
• Kentucky changed from 11.00% to 10.00% for underpayments and from 7.00% to 6.00% for overpayments.
• Louisiana changed from 11.75% to 11.25% for both underpayments and overpayments.
• Massachusetts changed from 9.00% to 8.00% for underpayments and from 7.00% to 6.00% for overpayments.
• Michigan changed from 9.50% to 9.47% for both underpayments and overpayments.
• Montana changed from 11.50% to 11.00% for both underpayments and overpayments.
• North Carolina changed from 8.00% to 7.00% for both underpayments and overpayments.
• New Hampshire changed from 9.00% to 10.00% for underpayments and from 6.00% to 7.00% for overpayments.
• New Jersey changed from 11.50% to 10.75% for underpayments and from 8.50% to 7.75% for underpayments.
• New Mexico changed from 8.00% to 7.00% for both underpayments and overpayments.
• New York City changed from 12.00% to 11.00% for underpayments and 7.00% to 6.00% for overpayments.
• New York State changed from 12.00% to 11.00% for underpayments and 7.00% to 6.00% for overpayments.
• Oregon changed from 8.00% to 9.00% for both underpayments and overpayments.
• Pennsylvania changed from 8.00% to 7.00% for underpayments and from 6.00% to 5.00% for overpayments.
• South Carolina changed from 8.00% to 7.00% for underpayments and from 5.00% to 4.00% for overpayments.
• Utah changed from 7.00% to 6.00% for both underpayments and overpayments.
• Virginia changed from 10.00% to 8.00% for both underpayments and overpayments.
• Vermont changed from 8.00% to 8.50% for both underpayments and overpayments.
• West Virginia changed from 13.00% to 12.25% for underpayments and from 11.50% to 10.75% for overpayments.

Texas changed from 9.50% to 8.50% for underpayments per an email from the State Comptroller’s Office; as of the release date of this version they had not published either the underpayments or overpayment rates.

As of the date of this release Maryland had not published its interest rates for 2025.

There were three rate changes that were previously announced by their respective jurisdictions:

• Colorado changed from 11.00% to 12.00% for both underpayments and overpayments.
• Nebraska will change from 5.00% to 8.00% for both underpayments and overpayments.
• New Hampshire will change from 9.00% to 10.00% for underpayments and from 6.00% to 7.00% for overpayments.

These were included in prior releases and carried forward into the 25.1.0.0 release.

There is only one change effective October 1, 2024. The Missouri refund rate changed from 3.10% to 3.20%; the underpayment rate remained unchanged at 9.00%.

Two rates were announced effective January 1, 2025, and these rates have been included in this release:

• Nebraska will change from 5.00% to 8.00% for both underpayments and overpayments.
• New Hampshire will change from 9.00% to 10.00% for underpayments and from 6.00% to 7.00% for overpayments.

Colorado had previously announced a change from 11.00% to 12.00% for both overpayments and underpayments; this change was included in the 24.3.0.0 release.

The following rate changes went into effect on July 1, 2024:

• California changed from 7.00% to 8.00% for underpayments; the refund rate remained unchanged at 5.00%. This change was available at the time the 24.2.0.0 release was issued and was included at that time.
• Michigan changed from 9.30% to 9.50% for both underpayments and overpayments.
• The Missouri refund rate changed from 3.00% to 3.10%; the underpayment rate remained unchanged at 9.00%.
• Tennessee changed from 12.25% to 12.50% for both underpayments and overpayments.

This release also includes a rate change for underpayments effective January 1, 2025, for Colorado from 11.00% to 12.00% for both underpayments and overpayments.

The file that contains information about extensions has been reduced to include only the automatic COVID-19 extensions granted in 2020 by the jurisdictions we track. For other extensions for relief in disaster situations, please consult that jurisdiction’s website. For federal disaster relief consult https://www.irs.gov/newsroom/tax-relief-in-disaster-situations. In the cases that we do not track use the Easy Calculation tab of Instant Interest to specify the revised due date for payment of taxes.

Only one rate change went into effect on April 1, 2024. The Missouri refund rate changed from 2.70% to 3.00%; the underpayment rate remained unchanged at 9.00%.

This release also includes a rate change for underpayments effective July 1, 2024, for California from 7.00% to 8.00%; the refund rate will remain unchanged at 5.00%.

The following rate changes became effective January 1, 2024. As noted with release 24.1.0.0, not all jurisdictions had published their rates for the first quarter of 2024 when that release was posted on January 2, 2024. The following changes have been added:

• Pennsylvania changed from 7.00% to 8.00% for underpayments and from 5.00% to 6.00% for overpayments.
• Rhode Island changed from 6.25% to 8.50% for overpayments; the rate for underpayments remained at 12.00%.
• Texas changed from 8.50% to 9.50% for underpayments and from 3.018% to 4.981% for overpayments.

In addition, programs change were made to accommodate four decimal places for the new Maryland rate of 10.0075% for both overpayments and underpayments.

The following rate changes became effective January 1, 2024 (NOTE: As of January 2, 2024, the date of this release, Alaska, Pennsylvania, and Texas had not yet published their rates for the first quarter of 2024; these may become available in an interim release later in the month):

• Colorado changed from 8.00% to 11.00% for both underpayments and overpayments.
• Florida changed from 11.00% to 12.00% for both underpayments and overpayments.
• Georgia changed from 10.50% to 11.50% for both underpayments and overpayments.
• Iowa changed from 6.00% to 10.00% for both underpayments and overpayments.
• Idaho changed from 5.00% to 6.00% for both underpayments and overpayments.
• Illinois changed from 7.00% to 8.00% for both underpayments and overpayments.
• Indiana changed from 2.00% to 4.00% for both underpayments and overpayments.
• Kansas changed from 6.00% to 8.00% for both underpayments and overpayments.
• Kentucky changed from 8.00% to 11% for overpayments and from 4.00% to 7.00% for overpayments.
• Louisiana changed from 9.50% to 11.75% for both underpayments and overpayments.
• Maryland changed from 9.00% to 10.0075% for both underpayments and overpayments. NOTE: Maryland’s decision to extend the rate to the fourth decimal of a percentage point was not anticipated. As a result, we will have to release an interim update. For the time being the rate is in Instant Interest as 10.008%.
• Maine changed from 7.00% to 10.00% for both underpayments and overpayments.
• Michigan changed from 8.25% to 9.30% for both underpayments and overpayments.
• Minnesota changed from 5.00% to 8.00% for both underpayments and overpayments.
• Missouri changed from 6.00% to 9.00% for underpayments and from 2.40% to 2.70% for overpayments.
• Montana changed from 9.25% to 11.50% for both underpayments and overpayments.
• North Carolina changed from 7.00% to 8.00% for both underpayments and overpayments.
• New Hampshire changed from 7.00% to 9.00% for underpayments and from 4.00% to 6.00% for overpayments.
• New Jersey changed from 11.25% to 11.50% for underpayments and from 8.25% to 8.50% for overpayments.
• Ohio changed from 5.00% to 8.00% for both underpayments and overpayments.
• Oregon changed from 6.00% to 8.00% for both underpayments and overpayments.
• Utah changed from 5.00% to 7.00% for both underpayments and overpayments.
• Vermont changed from 4.00% to 8.00% for both underpayments and overpayments.
• West Virginia changed from 11.50% to 13.00% for underpayments and from 10.00% to 11.50% for overpayments.

The following rate changes are effective October 1, 2023:

• Alaska changed from 10.50% to 10.75% for both underpayments and overpayments.
• Alabama changed from 7.00% to 8.00% for both underpayments and overpayments.
• Arizona changed from 7.00% to 8.00% for both underpayments and overpayments.
• Federal changed from 7.00% to 8.00% for underpayments and from 6.00% to 7.00% for overpayments.
• Massachusetts changed from 8.00% to 9.00% for underpayments and from 6.00% to 7.00% for overpayments.
• New Mexico changed from 7.00% to 8.00% for both underpayments and overpayments.
• New York City changed from 11.00% to 12.00% for underpayments and from 6.00% to 7.00% for overpayments.
• New York State changed from 11.00% to 12.00% for underpayments and from 6.00% to 7.00% for overpayments.
• South Carolina changed from 7.00% to 8.00% for underpayments and from 4.00% to 5.00% for overpayments.
• Virginia changed from 9.00% to 10.00% for both underpayments and overpayments.

The following rate changes will become effective January 1, 2024:

• Colorado will change from 8.00% to 11.00% for both underpayments and overpayments.
• Maine will change from 7.00% to 10.00% for both underpayments and overpayments.
• New Hampshire will change from 7.00% to 9.00% for underpayments and from 4.00% to 6.00% for overpayments.