California Form 5805 – Fill Out and Use This PDF

California Form 5805 PDF Details

California Form 5805 is the state's Underpayment of Estimated Tax form, required when individual taxpayers and fiduciaries owe a penalty for failing to make sufficient estimated tax payments during the year. This form is filed as an attachment to your California income tax return (Form 540, Form 540A, Form 540NR, or Form 541).

Who Must File Form 5805

You are required to file California Form 5805 if you had estimated tax underpayments and your total tax liability exceeds the minimum filing threshold. You must also attach this form if you want to calculate your own penalty rather than letting the California Franchise Tax Board (FTB) compute it, or if you qualify for a penalty exception that you need to document on your return.

Conditions for Penalty Exceptions

Several conditions can reduce or eliminate the underpayment penalty. You may be exempt if at least 80% of your adjusted gross income for the current year was subject to California income withholding, or if your net tax liability minus allowable credits falls below the minimum threshold. Taxpayers who experienced extraordinary circumstances beyond their control may also qualify for a penalty waiver from the FTB.

Annualized Income Installment Method

Taxpayers with uneven income throughout the year can use the annualized income installment method to calculate a potentially lower penalty. This approach aligns each estimated tax installment with the income actually earned in each period, rather than applying a uniform quarterly payment requirement. If your income was higher in later quarters, this method can significantly reduce the calculated penalty on your California tax filing.

Frequently Asked Questions

Can the FTB calculate the penalty for me?

Yes. The California Franchise Tax Board can calculate the underpayment penalty on your behalf. However, if you believe you qualify for an exception or want to use the annualized income installment method, you must complete and attach Form 5805 to your income tax return.

What returns does Form 5805 attach to?

Form 5805 is an attachment to California individual and fiduciary income tax returns: Form 540, Form 540A, Form 540NR (for part-year and nonresident taxpayers), and Form 541 (for fiduciaries).

Do I need to file Form 5805 every year?

No. You only need to file Form 5805 in years when you have an underpayment of estimated tax and owe a penalty, or when you want to document an exemption from the penalty on your California income tax return.