Summary

The Excel NETWORKDAYS.INTL function counts the number of working days between two dates using custom weekend rules. It can also exclude optional holidays from the result.

This makes it useful for international teams, regional schedules, six-day workweeks, support operations, project planning, and any workbook where the weekend is not always Saturday and Sunday.

Syntax

=NETWORKDAYS.INTL(start_date, end_date, [weekend], [holidays])

start_date and end_date define the period you want to measure. The optional weekend argument tells Excel which days are treated as non-working days, and holidays lets you exclude additional dates.

This extra weekend argument is what makes NETWORKDAYS.INTL more flexible than the standard NETWORKDAYS function. If your workbook has to support different countries, departments, or shift patterns, this version is often the better choice.

Arguments

• start_date - The first date in the period.
• end_date - The last date in the period.
• weekend - [optional] A weekend code or a 7-character string that marks non-working days.
• holidays - [optional] A range or array of dates to exclude from the workday count.

Microsoft notes that the start and end dates can be earlier, later, or the same as each other. That means the function is flexible enough for forward planning, backward checks, or same-day tests.

Weekend Options

The weekend argument can be entered in two main ways: with a weekend code or with a weekend string.

Microsoft documents that weekend strings always start with Monday and end with Sunday. In that string, 1 means a non-workday and 0 means a workday. That makes the pattern explicit and easier to audit in complex models.

Using NETWORKDAYS.INTL

NETWORKDAYS.INTL is especially useful when a standard Monday-to-Friday calendar is not enough. For example, some teams may work Sunday to Thursday, some may use a six-day workweek, and others may follow regional calendars with Friday-Saturday weekends.

The function is also useful when the same workbook serves multiple locations. Instead of forcing every team into one weekend rule, you can adjust the weekend code or weekend string so the calculation reflects the actual local schedule.

Like NETWORKDAYS, this function can also exclude holidays. That means the final count can reflect both the local weekend pattern and the actual closure days that should not be treated as working time.

Example 1 - Use a Custom Weekend Code

This example counts workdays using weekend code 17, where Saturday is the only weekend day.

=NETWORKDAYS.INTL(B1,B2,17)

This is useful for six-day workweeks where Sunday still counts as a working day. It is a good reminder that not every schedule follows the standard Saturday-Sunday weekend.

Example 2 - Use a Weekend String

A weekend string can make the weekend rule easier to read directly in the formula.

=NETWORKDAYS.INTL(B1,B2,"0000011")

Because the string starts with Monday, this pattern means Monday through Friday are workdays and Saturday-Sunday are weekends. This form is helpful when you want the rule to be more obvious to anyone reviewing the model.

Example 3 - Test a Business-Day Threshold

NETWORKDAYS.INTL is often used inside logical tests when deadlines depend on local schedules.

=NETWORKDAYS.INTL(B1,B2,1)>10

This returns TRUE if the business-day window is greater than ten and FALSE otherwise. It is useful for SLA checks, staffing rules, and project controls.

Example 4 - Convert Custom Workdays into a Cost

Once you have the custom workday count, you can multiply it by a daily rate.

=NETWORKDAYS.INTL(B1,B2,1)*200

This is useful for payroll estimates, contractor billing, and resource planning where cost depends on the number of actual working days rather than simple calendar days.

Conclusion Recap

• Summary: NETWORKDAYS.INTL counts working days using custom weekend rules.
• Main advantage: It handles non-standard workweeks that NETWORKDAYS cannot.
• Weekend setup: You can use either preset weekend codes or a 7-character weekend string.
• Holiday support: You can exclude additional dates such as public holidays or closure days.
• Common uses: International schedules, regional SLAs, payroll, billing, and project planning.
• Best practice: Use the weekend string when you want the schedule to be more explicit and easier to review.