Pennsylvania Form REV-1630A – Underpayment of Estimated Tax by Individual Farmers (2026)

Last reviewed: 2025-11-11

Use the Pennsylvania Tax Form Calculator Pennsylvania Form REV-1630A – Underpayment of Estimated Tax by Individual Farmers as a stand alone tax form calculator to quickly calculate specific amounts for your 2026 Pennsylvania state tax return. Alternatively, you can use one of our Combined Federal and State Tax Estimators to quickly calculate your salary, tax, and take-home pay.

Form REV-1630A is used by individual farmers to calculate any underpayment of estimated Pennsylvania income tax and determine if they qualify for the farmer’s exception. This exception applies when at least two-thirds (66⅔ %) of a taxpayer’s total gross income for the year comes from farming. If eligible and the full estimated payment was made by January 15, the farmer may avoid any underpayment interest under Pennsylvania’s estimated tax rules.

The form also helps compute potential interest penalties if payments were late or insufficient, ensuring accurate compliance with Pennsylvania’s 3.07 % personal income tax requirements.

How to Complete Form REV-1630A

Step 1 – Determine Qualification: In the Farming Exception Worksheet, enter your total gross income and gross income from farming. If farming income equals or exceeds 66⅔ % of total income, check “Yes” to confirm eligibility for the farmer’s exception.

Step 2 – Calculate Underpayment: Compute your total tax liability (PA-40 Line 12), subtract available credits, and compare to estimated payments made by January 15. The remaining balance is the underpayment amount.

Step 3 – Apply Safe-Harbor Rule: Section II compares your payments and withholding to 100 % of the prior year’s tax to check if the safe-harbor condition is met. If payments meet or exceed that amount, no interest applies.

Step 4 – Compute Interest (if required): Section III calculates daily interest from January 15 until payment or return filing using the official rate in effect (0.000192 per day by default).

Examples

Example 1 – Farmer Exempt: Chris’s total income is $90 000, of which $65 000 (72 %) is from farming. Chris paid the entire estimated tax by January 15 and qualifies for the exception — no penalty applies.

Example 2 – Partial Farming Income: Jordan earns $100 000 total, $55 000 from farming (55 %). Because farming income is less than 66⅔ %, the farmer’s exception does not apply. Any unpaid tax after January 15 is subject to interest computed in Section III.

Example 3 – Late Payment: Pat qualifies as a farmer but pays the estimated tax 45 days after January 15. The penalty equals 45 days × daily rate × underpaid amount, calculated automatically in the table.

Further Guidance and Related Forms

• Form REV-1630 – Underpayment of Estimated Tax by Individuals
• Form PA-40 – Individual Income Tax Return
• Pennsylvania Department of Revenue – Personal Income Tax Forms

Farmers who make at least two-thirds of their income from agricultural activity may file Form REV-1630A instead of REV-1630 to determine if interest penalties apply. Accurate reporting of farming income and timely payment help avoid unnecessary penalties and ensure compliance with Pennsylvania’s estimated tax rules.

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Important Notes

All calculations are estimates for guidance only. Always review your return and consider professional advice when submitting official filings.