Interest Rates
The interest rate applied to unpaid or underpaid taxes is based on the rate charged by the Internal Revenue Service plus 3 percent. Every January and July the CDTFA evaluates the rates. If the CDTFA determines that a rate change is required, the change takes effect 6 months later and remains in effect for at least 6 months.
An interest calculator is available to help you calculate the interest due.
For more information about when interest applies and when you may be relieved of interest charges, see publication 75, Interest and Penalties
| Period Beginning – Ending |
"Debit" Rate for Deficiencies | "Credit" Rate for Refunds | Monthly Factor |
|---|---|---|---|
| 01/01/21 – 06/30/21 | 6% | 0% | .00500 / .00000 |
| 07/01/20 – 12/31/20 | 8% | 2% | .00667 / .00167 |
| 01/01/20 – 06/30/20 | 8% | 2% | .00667 / .00167 |
| 07/01/19 – 12/31/19 | 9% | 2% | .0075 / .00167 |
| 01/01/19 – 06/30/19 | 7% | 2% | .00583 / .00167 |
| 07/01/18 – 12/31/18 | 7% | 1% | .00583 / .00083 |
| 01/01/18 – 06/30/18 | 7% | 1% | .00583 / .00083 |
| 07/01/17 – 12/31/17 | 7% | 1% | .00583 / .00083 |
| 01/01/17 – 06/30/17 | 7% | 0% | .00583 / .00000 |
| 07/01/16 – 12/31/16 | 6% | 0% | .00500 / .00000 |
| 01/01/16 – 06/30/16 | 6% | 0% | .00500 / .00000 |
| 07/01/15 – 12/31/15 | 6% | 0% | .00500 / .00000 |
| 01/01/15 – 06/30/15 | 6% | 0% | .00500 / .00000 |
| 07/01/14 – 12/31/14 | 6% | 0% | .00500 / .00000 |
| 01/01/14 – 06/30/14 | 6% | 0% | .00500 / .00000 |
| 07/01/13 – 12/31/13 | 6% | 0% | .00500 / .00000 |
| 01/01/13 – 06/30/13 | 6% | 0% | .00500 / .00000 |
| 07/01/12 – 12/31/12 | 6% | 0% | .00500 / .00000 |
| 01/01/12 – 06/30/12 | 7% | 0% | .00583 / .00000 |
| 07/01/11 – 12/31/11 | 6% | 0% | .00500 / .00000 |
| 01/01/10 – 06/30/11 | 7% | 0% | .00583 /.00000 |
| 07/01/09 – 12/31/09 | 8% | 0% | .00667 /.00000 |
| 01/01/09 – 06/30/09 | 8% | 2% | .00667 /.00167 |
| 07/01/08 – 12/31/08 | 10% | 3% | .00833 /.0025 |
| 01/01/07 – 06/30/08 | 11% | 5% | .00917 /.00417 |
| 07/01/06 – 12/31/06 | 10% | 4% | .00833 /.00333 |
| 01/01/06 – 06/30/06 | 9% | 3% | .0075 /.0025 |
| 07/01/05 – 12/31/05 | 8% | 2% | .00667 /.00167 |
| 07/01/04 – 06/30/05 | 7% | 1% | .00583 /.00083 |
| 07/01/03 – 06/30/04 | 8% | 1% | .00667 /.00083 |
| 07/01/02 – 06/30/03 | 9% | 2% | .0075 /.00167 |
| 01/01/02 – 06/30/02 | 10% | 4% | .00833 /.00333 |
| 01/01/01 – 12/31/01 | 12% | 6% | .010000 /.00500 |
Notes
- These rates do not apply to the IFTA (International Fuel Tax Agreement) program. For more information on IFTA rates, you can visit the International Fuel Tax Agreement (IFTA) – Interest Rates page.
- These rates do not apply to the Timber Yield Tax. For more information on Timber Yield Tax rates, you can visit the Timber Yield Tax Interest Rates page.
- Applied to each month or fraction of a month that a tax or fee payment is overdue or a refund is owed.