In December your employer works out your income tax for the whole year and settles it against the tax taken from each payslip. This is the year-end adjustment, nenmatsu chōsei. The 2026 tax reform raised the basic deduction to 1,040,000 yen for salaries up to about 6.65 million yen, but every payslip of 2026 was taxed with tables built on 580,000 yen. The December adjustment settles the difference, the National Tax Agency says, so I built a calculator for it.
What comes back
The year-end adjustment calculator asks for your monthly pay, the months this employer pays you in 2026, bonuses, your age and your family. On 300,000 yen a month for the whole year with no family, 76,080 yen is taken during the year and the tax for the year is 44,400 yen, so 31,680 yen comes back with your last pay. The old rules would have charged 52,600 yen, 8,200 yen more. Insurance, iDeCo, a housing loan and the tax on your own payslip go under one more button.
If you started this year
The tax on each payslip assumes you earn that pay for twelve months. Start in April on the same 300,000 yen and 38,060 yen comes back.
The forms, and family abroad
Below the calculator, the page explains what each of the four forms is for and gives its Japanese name. A spouse or parents living abroad count only with proof that they are your relatives and of the money you sent them. From age 30 to 69 they also need at least 380,000 yen from you this year, unless they study abroad or are disabled. If you leave Japan before December, your adjustment uses the old rules, and only a tax return brings you the new deductions.
The page works in the seven languages of the Hub, and the net salary calculator now shows your estimate too.
