How to calculate the amount of national health insurance tax ( Kokumin kenkou hoken ryou = 国民健康保険料 ) in Japan
The calculation formula of national health insurance tax is different from each city.
So, in this page this is just for reference.
( This calculation formula is based on Setagaya ward, Tokyo, year of 2015. )
1 Check the amount of income ( Shotoku kingaku ).
The amount of income = earnings ( shuu nyuu ) – deductible expense ( Keihi ).
In the case of salaried workers.
The amount of income = The amount of salary – employment income deduction ( Kyuuyo shotoku koujo ).
In the case of self employee.
The amount of income = The amount of sales – deductible expense.
This is a part of application form for blue income tax return.
In the case of salaried worker.
This is a part of slip of withholding income tax.
２ Deduct 330,000 yen from the amount of income and calculate base amount.
Assumed that you are a self employee and have a wife and a child.
All persons are enrolled in national health insurance.
You ( 40 years old ) are managing business without legal entity and your wife ( 39 years old ) sometimes assist your business.
You pay salary to your wife.
The amount of your sales is 12,000,000 yen per a year.
Deductible expense other than salary to your wife : 6 million yen.
The amount of your wife’s salary : 1 million yen.
The amount of business income : 5,000,000 yen.
( 12,000,000 yen. – 6,000,000 yen – 1,000,000 yen = 5,000,000 yen )
Your base amount : 6,000,000 yen – 330,000 yen = 5,670,000 yen.
Your wife : The amount of income is 1,000,000 yen.
1,000,000 yen – 650,000 yen ( employement income deduction = kyuuyo shotoku koujo ) – 330,000 yen = 20,000 yen.
This is base amount of your wife.
Child : 12 years old.
The amount of income : 0 yen.
Total base amount : 5,670,000 yen + 20,000 yen = 5,690,000 yen.
３ Let’s calculate the amount of per capita basis ( Kintou wari ).
You can calculate the amount of per capita basis ( Kintou wari gaku ) based on the number of family members.
(a) The number of family member × 33,900 yen 3 persons ×33,900 yen ＝101,700 yen.
(b) The number of family member × 10,800 yen 3 persons ×10,800 yen ＝ 32400 yen.
(c) The number of family member of age of 40 ～64 × 14,700 yen 1 person ×14,700 yen ＝14,700 yen.
Total (a)+(b)+(c) = 101,700 yen＋32,400yen＋14,700 yen＝148,800 yen
This amount is called taxation on per capita basis ( Kintou wari gaku ).
4 Let’s calculate the amount of taxation on per income basis ( Shotoku wari gaku ).
(d) Base amount of 5,690,000 yen ×6.45% ＝367,005 yen.
(e) Base amount of 5,690,000 yen ×1.98%＝112,662 yen.
(f) The amount of person his/her age is from 40 ～64 ×1.50% 5,670,000 yen×1.50%＝85,050 yen
Total (d) + (e) + (f) = 367,005 yen + 112,662 yen + 85,050 yen = 564,717 yen.
This amount is called taxation on per income basis ( Shotoku wari gaku).
5 Let’s add up taxation on per income basis ( Shotoku wari gaku ) and taxation on per income basis ( Shotoku wari gaku).
148,800 yen + 564,717 yen = 713,517 yen.
This amount is annual national health insurance tax.
6 Maximum amount of national health insurance tax.
There is maximum amount of national health insurance tax.
(a) + (d) = 520,000 yen
(b) + (e) = 170,000 yen
(c) + (f) = 160,000 yen
Annual maximum amount : 850,000 yen.
The amount of national health insurance differs depending on city you live.
According to city, the amount differs more than 200,000 yen per a year.
