Part I is Questions, Part II is Required Annual Payment and Part III is Annualized Income Installment Method Schedule.
Attach: Attach this form to the back of your Form 540, Form 540NR, or Form 541.
Waiver: If you are requesting a waiver of the penalty, provide an explanation and check the box on Form 540, line 113; Form 540NR, line 123; or Form 541, line 45.
Annualized income: Use Part III only if you earned taxable income at an uneven rate during 2025.
Total underpayment: subtract line 9 from line 6; if the total underpayment is zero or less, stop here: you do not owe the penalty and do not file form FTB 5805.
| Question | Answer |
|---|---|
| Form Name | Form 5805 |
| Form Length | 4 pages |
| Fillable? | Yes |
| Fillable fields | 123 |
| Avg. time to fill out | 21 min |
| Edition | 2025 |
| Matches the agency's file | Yes, checked October 2, 2026 |
| Other names | 5805, FTB 5805, CA 5805, Form 5805, California Form 5805, Underpayment of Estimated Tax by Individuals and Fiduciaries |
| Official source | Form 5805 (Rev 2025), California Franchise Tax Board |
California Form 5805 isn’t the one you’re looking for?