Most states with an income tax copied the federal penalty structure: a percentage per month for filing late, a smaller one for paying late, plus interest. But they set their own rates and their own interest formulas. Three things to know before the state-by-state notes:
- Separate clocks. Fixing your federal problem doesn't fix the state one. Each expects its own return, payment, and (if needed) abatement request.
- Different interest. States set their own rates on their own schedules, some quarterly, some annually, and several charge noticeably more than the IRS.
- Relief exists there too. Most states offer reasonable-cause relief, and several have first-time abatement analogues. Always worth asking.
California (Franchise Tax Board)
The heavyweight. Late filing costs 5% of unpaid tax per month up to 25%, like the IRS, with a minimum penalty once a return is very late. The late-payment penalty starts at 5% of the unpaid amount plus 0.5% per month (capped), which makes California's payment penalty front-loaded and harsher than the federal one for short delays. Interest is set twice a year. S corporations and partnerships face per-owner late-filing penalties similar in structure to the federal ones. Check current rates at ftb.ca.gov.
New York
Follows the federal template closely: 5% per month late-filing up to 25%, 0.5% per month late-payment, with interest set quarterly. New York's interest rate on unpaid income tax has run higher than the IRS rate in recent years. New York is also notably aggressive about driver's-license suspension and collection on large unpaid balances. Check tax.ny.gov.
Texas & Florida
No personal income tax, so there's no state penalty on a late 1040-equivalent. For individuals, the federal bill is the whole bill. Businesses aren't off the hook: Texas franchise tax and both states' sales taxes carry their own late penalties with short fuses, and those bite LLCs and corporations that assume "no income tax" means "no deadlines."
Pennsylvania
A flat-rate income tax state (3.07%) with a familiar structure: 5% per month late-filing penalty (capped), a smaller late-payment charge, and interest at an annually-set rate. Pennsylvania is strict about its estimated-payment rules for self-employed residents. Check revenue.pa.gov.
Will we build state calculators?
Maybe. Accuracy is the constraint: fifty states times quarterly-changing rates is a big maintenance surface, and we'd rather cover fewer states exactly than all fifty approximately. If you'd use a calculator for your state, tell us: contact@whatsmypenalty.com.