Section 19144 Of Article 7. Penalties And Additions To Tax From California Revenue And Taxation Code >> Division 2. >> Part 10.2. >> Chapter 4. >> Article 7.

. For the purposes of Section 19142 the amount of the underpayment shall be the excess of--
  (a) (1) The amount of the installment which would be required to be paid if the estimated tax were equal to the applicable percentage of the tax shown on the return for the taxable year, or (2) in the case of the tax imposed by Article 3 (commencing with Section 23181) of Chapter 2 of Part 11 an amount equal to the applicable percentage of the lesser of the tax computed at the rate provided by Section 19024 (but otherwise on the basis of the facts shown on the return and the law applicable to the taxable year), or the tax shown on the return for the taxable year as prescribed by Section 19021, or (3) if no return was filed, the applicable percentage of the tax for that year, over
  (b) The amount, if any, of the installment paid on or before the last date prescribed for payment.
  (c) For purposes of this section, the "applicable percentage" shall be as follows:
  (1) For taxable years beginning before January 1, 1998, 95 percent.
  (2) For taxable years beginning on or after January 1, 1998, 100 percent.