FREE WEB TOOL

Business days calculator

Calculate business days between two dates with optional Japanese holidays, custom working weekdays, endpoint inclusion, and custom closure dates or ranges.

Use tool

Start dateEnd dateExcluded dates YYYY-MM-DD (optional)

How to use this tool

Calculate business days between two dates with optional Japanese holidays, custom working weekdays, endpoint inclusion, and custom closure dates or ranges.

Set Start date, End date, Excluded dates YYYY-MM-DD (optional).
Use Calculate to process the input.
Compare the result with your source data and return to the input to make corrections.

Input and settings example

2026-09-01 to 2026-09-30: 22 weekdays with no exclusions; 20 when September 21 and 22 are excluded.

Both endpoints are included. Public holidays are not excluded automatically; enter closure dates as YYYY-MM-DD, one per line.

Japanese holiday rules are based on the Cabinet Office holiday-law information and published 2026–2027 holiday dates. Cabinet Office source

What to know before using it

Japanese schedules can include national holidays, substitute holidays, citizens’ holidays, company shutdowns and custom working weekdays. Start/end inclusion also changes counts.

Common failure points

Company shutdowns must be entered separately from national holidays.
Whether day zero counts depends on the business rule.
Cross-border deadlines require the other country’s holidays and timezone too.

Practical example

September 21–23, 2026 are consecutive Japanese holidays, so a Mon–Fri schedule with Japanese holidays excluded yields zero business days.