The biggest mistake in 故鄉稅 is donating beyond your personal “deduction ceiling.” Any amount above this cap is a pure out-of-pocket donation. We explain how your ceiling is determined and how to calculate it accurately using online calculators.

Factors Determining Your Ceiling

Your maximum deductible contribution depends on your “annual gross income” and “family structure” (dependents, spouse).

• Higher Gross Income: Raises your deduction ceiling.
• More Dependents: Lowers your 故鄉稅 limit due to pre-existing tax write-offs.

How to Calculate Your Limit

1. Retrieve Your Annual Tax Slip (源泉徴収票)

Salaried workers should check their year-end tax slip for “income after deductions” and “total deductions.”

2. Run Portal Simulation Tools

Furusato portals host basic calculators (requiring only annual income and family size) and advanced calculators (requiring detailed inputs from your tax slip). Use the advanced tools for precision.

Staying Safe Close to the Ceiling

Claiming medical expense deductions or new mortgage tax write-offs in the same fiscal year reduces your 故鄉稅 ceiling. Leave a buffer when calculating.