The total population of Japan is 127,185,332 people. The people of Japan speak the Japanese language. The linguistic diversity of Japan is almost homogeneous according to a fractionation scale, which is 0.0178 for Japan. The average age is around 46.1 years. Life expectancy in Japan is 84. Female fertility rate in Japan is 1.4. About 5% of the population of Japan is obese. Ethnic diversity is nearly uniform according to a fractionation scale, which for Japan is 0.0119. Details of the language, religion, age, gender distribution and advancement of the people of Japan can be found in the sections below, as well as the section on education in the country.

Population
In Japan, the population density is 335.58 people per square kilometer (873 per square mile). Based on these statistics, this country is considered densely populated. The total population of Japan is 127,185,332 people. Japan has approximately 2,043,877 foreign immigrants. Immigrants in Japan account for 1.1 percent of the total number of immigrants worldwide. Immigrants in Japan account for 1.9 percent of the total number of immigrants worldwide. The ethnic diversity of Japan is nearly uniform according to an ethnicity-based fractionation scale. Ethnic Fractionation (EF) deals with the number, size, socioeconomic distribution, and geographic location of diverse cultural groups, usually within a state or some other demarcated area. Specific cultural characteristics can refer to language, skin color, religion, ethnicity, customs and traditions, history, or other distinctive criteria, alone or in combination. These characteristics are often used for social exclusion and power monopolization. The index of ethnic fractionation in Japan is 0.0119. This means that the people living in Japan are somewhat fractional. EF is usually measured as 1 minus the Herfindahl concentration index of ethnolinguistic group proportions, which reflects the probability that two randomly drawn individuals from the population belong to different groups. The theoretical maximum of EF of 1 means that each person belongs to a different group. Read Japan's average age and gender distribution statistics at different ages below.

Age
The average age is around 46.1 years. The median age for men is 44.8 years, while the median age for women is 47.5 years.

Gender
The sex ratio, or number of males per female (estimated at birth), is 1.06. It can be further broken down into the following categories: sex ratio below 15 - 1.06; sex ratio from 15 to 64 - 1.02; sex ratio over 64 - 0.74; Overall sex ratio - 0.95. The overall sex ratio differs from the sex ratio estimated at birth. This is because some newborns are included in the sex ratio estimated at birth, but die within the first few weeks of life and are not included in the overall sex ratio.

Religion
The majority religion in Japan is Buddhism, whose adherents make up 36.2% of all religious believers in the country. Buddhism is a nontheistic religion or philosophy (Sanskrit: धर्म Dharma; Pali: धम्म Dhamma) encompassing a variety of traditions, beliefs, and spiritual practices based largely on teachings attributed to Gautama Buddha, commonly known as the Buddha (the awakened). According to Buddhist tradition, the Buddha lived and taught sometime between the sixth and fourth centuries BC. in the eastern part of the Indian subcontinent. He is recognized by Buddhists as an awakened or enlightened teacher who shared his insights to help sentient beings end their suffering through the elimination of ignorance and craving. Buddhists believe this is achieved through direct understanding and perception of dependent origination and the Four Noble Truths. In addition to Buddhism, there are several other religions in the country. Other religions in Japan are Christianity, Buddhism, folk religions. The religious diversity of Japan is quite diverse according to a fractionation scale based on the number of religions in Japan. The index of religious fractionation in Japan is 0.5406. This score means there are several major religions evenly distributed in Japan.