Tools
Date and time tools
Tools for date calculation, day counts, age checks from a birth date, and Japanese era names.
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Japanese era
Japanese Year / Date Era Converter
Convert Gregorian years and dates into Japanese era notation from Meiji onward, including Reiwa, Heisei, Showa, and exact era transition dates.
Era table
Japanese Era Table
Check a year-by-year table of Gregorian years, Japanese era names, zodiac animals, and sexagenary cycle labels.
Age & Days
Age & Days Since Birth Calculator
Calculate age, days since birth, the next birthday, and days remaining from a birth date and reference date.
Days
Days Between Dates Calculator
Enter a start date and an end date to get the date difference and the inclusive count that includes the start date. Year boundaries and leap years follow the calendar, and business days are handled by the business day calculator.
Business Day Calc
Business Day Calculator (Excl. Weekends/Holidays)
Calculate an estimated date "N business days" in the future or past from a specific start date, excluding weekends and Japanese public holidays.