This page estimates how much you can donate through hometown tax donations while keeping your net cost at ¥2,000.

Enter only annual salary and family composition. Detailed deductions are not included.A rough guideis all this estimate is intended to provide.

Estimate for donations made in 2026 (FY2027 resident tax).Assumes salary income of ¥8.5 million or less, no other income, a spouse under 70, dependents aged 16 to under 70, and each spouse/dependent having total income of ¥620,000 or less (salary-only gross income of ¥1.36 million or less). Excludes dependents under 16, special spouse or specified-relative deductions, and special tax exemptions for disability or similar circumstances.

What Does This Calculation Do?

The hometown donation limit derives from the resident tax special-credit ceiling. The Local Tax Act caps the credit at twenty percent of the taxpayer’s income-based resident tax. Thus,20 percent of income-based resident taxis the ceiling.

This page calculates employment income from gross salary, deducts social insurance, the basic deduction, spouse deduction, and dependent deductions to obtain resident-tax taxable income, then calculates income-based tax and the adjustment credit. It divides 20 percent of post-adjustment income-based tax by the percentage applicable to 2026 donations and adds ¥2,000. For standard comprehensive taxation, the percentage is 90 percent minus income tax rate × 1.021, reflecting Special Income Tax for Reconstruction.

The underlying mechanism is explained in How Do Hometown Donations Work Under Tax Law? with statutory references.

What This Calculation Excludes

• Housing loan credit. The 20-percent ceiling uses resident tax before that credit, but combined relief may not be fully usable. This calculator does not make that adjustment.
• Medical expense, life insurance, earthquake insurance, widow, single-parent, and disability deductions.
• iDeCo contributions (small enterprise mutual aid and similar contribution deduction). Higher contributions lower the limit.
• Non-salary income, including business, real estate, share capital gains, and dividends.
• Dependents under 16. They do not qualify for dependent deductions but affect exemption thresholds, so these cases are excluded.
• Whether you live in a designated city. Combined tax rates and ceiling percentages are the same, so the result changes little.

Sources of the Figures

• Employment income follows the table for 2026 receipts, reflecting the ¥740,000 minimum employment-income deduction, lower-income graduated calculations, and ¥4,000 increments below ¥6.6 million. It does not reproduce every rounding rule used in tax returns; displayed donation estimates are rounded down to the nearest ¥1,000.
• The resident tax basic deduction of ¥430,000, spouse deduction of ¥330,000, and dependent deduction of ¥330,000 (¥450,000 for ages 19 to under 23) come from Local Tax Act Article 314-2.
• The standard 10-percent income-based resident tax rate, adjustment credit, special-credit percentage table, and 20-percent ceiling follow Articles 314-3, 314-6, 37-2 paragraph 11, and 314-7 paragraph 11.
• The three relief formulas—income tax, basic resident tax credit, and special resident tax credit—and the special component’s 20-percent ceiling follow the same approach as the Ministry of Internal Affairs and Communications’ hometown donation portal explanation, About Tax Deductions and Credits.
• The 15-percent social-insurance assumption when left blank is an estimation input, not a statutory rule. Entering actual amounts from pay statements or the withholding slip improves accuracy.

Final Note

This is an estimate. Donations above the limit increase your net cost, so allow a margin. Past resident tax statements can help as a reference, but the current-year limit must use estimated current-year income and deductions to calculate next year’s income-based resident tax. The 20-percent ceiling uses tax after the adjustment credit and before other credits. Past statements alone cannot establish an accurate amount when income or deductions change.

Sources Checked for This Calculation and Explanation

• Local Tax Act, Articles 37, 37-2, 314-6, and 314-7, and Supplementary Provisions Article 5-6(Personal-deduction difference adjustments, adjustment credit, and applicable percentages)
• National Tax Agency: Increase in the Income Tax Basic Deduction and Other FY2026 Tax Reforms
• Osaka City: FY2027 Municipal and Prefectural Resident Tax Changes(Calculation of employment income received in 2026)
• Ikoma City: Hometown Donation Credit Amounts(Relationship between the 20% limit and housing loan credit; see the explanation for 2026 donations)