Living in Japan

Forms in Japan use era years, apartment ads use tatami mats, and ages are counted two ways. Start here.

Three things that confuse newcomers

Official forms often show the year as an era year, such as Reiwa 8, instead of 2026. Apartment listings give room sizes in tatami mats (jō) as well as in square meters, and the mats are not all the same size. And people in Japan sometimes give their age in a second way, called kazoedoshi, that adds one or two years to the age you are used to.

The pages in this section explain each of these and give you a calculator where one helps, so you can check a date on a form or the real size of a room without guessing.

Where to start

For era years on a driver's license, a tax form or a receipt, use the era converter. For rooms, use the tatami calculator, and read the guide to floor plans if terms like 1LDK or 6 jō are new to you. For ages and school years, read the guide to how ages are counted. For planning time off, the Japan holidays page lists every public holiday in 2027 and shows how much paid leave turns them into a longer break.

A note on accuracy

The tools run on fixed rules: the start dates of each era, the dimensions of the common mat types, and the legal conversion between tsubo and square meters. Customs, such as how some families count age for celebrations, vary from place to place, and the guides say so when that is the case. For official procedures, always confirm with the office, landlord or agent concerned.

If you are shopping rather than settling in, the Shopping in Japan section has the shoe and clothing size converters.

Last updated: 2026-10-04