What is marginal tax rate? Why do some people get ¥110,000 back and others ¥80,000 for the same dependent deduction?
Sources: NTA public materials and practical guidance from this tool. Last updated: 2026-06-19. Tax rules may change; follow your local tax office’s latest requirements.
Brief answer: Marginal tax rate is the income tax rate applied to your last bracket of income. Dependent deduction refund = deduction amount × marginal rate. Higher income generally means larger refunds.
Detailed explanation
Japanese income tax uses progressive rates. Dependent deduction reduces tax at your highest marginal bracket. Workers earning ¥5 million vs. ¥8 million with the same ¥580,000 deduction differ by about ¥29,000 due to 15% vs. 20% marginal rates. Estimate from withholding slip salary income after salary income deduction against the rate table. Resident tax is calculated separately at 10%. Spousal and dependent deductions stack with marginal effect based on your salary. This tool estimates from withholding slip data; final calculation is by the tax office.
Sources: NTA: Tax rates