Which holidays does this counter apply?

All 16 Japanese national holidays defined by the Act on National Holidays, including New Year's Day, Coming of Age Day, Greenery Day, Marine Day, Mountain Day, Respect for the Aged Day, and Culture Day. The Emperor's Birthday is placed on 23 February for years from 2020 onward.

How are the equinox holidays calculated?

Vernal Equinox Day (around 20 March) and Autumnal Equinox Day (around 23 September) shift year to year with the astronomical equinox. This tool uses the standard government approximation formula, which is accurate for the late 20th and 21st centuries.

What is a substitute holiday (振替休日)?

When a national holiday falls on a Sunday, the next non-holiday day becomes a substitute public holiday. The counter detects this automatically and excludes that substitute day from the working-day total.

What is a citizens' holiday (国民の休日)?

A weekday squeezed between two national holidays becomes a citizens' holiday. The classic example is the Silver Week gap in September. The tool inserts these sandwiched days and excludes them too.

Does this tool count weekends as working days?

No. It assumes a standard Monday-to-Friday working week. Saturdays and Sundays are reported separately and never counted as working days, matching typical Japanese payroll and SLA conventions.

Japan Working Day Counter

This counter tells you how many actual working days fall between two dates in Japan, after removing Saturdays, Sundays, and every national holiday — including the ones most calculators miss, such as the shifting equinox days, substitute holidays, and the citizens’ holidays that appear during Silver Week.

How it works

For each year in your range the tool builds the full set of Japanese public holidays, then walks the range day by day, classifying each as a working day, weekend, or holiday.

fixed dates   : New Year, Constitution Day, Children's Day, Culture Day, ...
moving Mondays : Coming of Age (2nd Mon Jan), Marine Day (3rd Mon Jul),
                 Respect for the Aged (3rd Mon Sep), Sports Day (2nd Mon Oct)
equinox days  : floor(20.8431 + 0.242194*(Y-1980) - floor((Y-1980)/4))  [spring]
                floor(23.2488 + 0.242194*(Y-1980) - floor((Y-1980)/4))  [autumn]
substitute    : holiday on Sunday  ->  next free day is a holiday
citizens' day : weekday between two holidays  ->  also a holiday

A working day is any Monday-to-Friday date that is not in that holiday set.

Example and notes

Japan’s Golden Week, the cluster of holidays from 29 April to 5 May, can wipe out most of a week’s working days once weekends and substitute days are included. Because the equinox dates and Monday-based holidays move each year, always let the tool compute them rather than assuming fixed dates. The equinox approximation is reliable for the 21st century but can be off by a day far outside that window.