Excel NETWORKDAYS and WORKDAY with Bank Holidays (Auto-Updating)

The formulas

=NETWORKDAYS(A2, B2, Holidays!A:A)        // business days between two dates (inclusive)
=WORKDAY(A2, 10, Holidays!A:A)            // 10 business days after A2
=NETWORKDAYS.INTL(A2, B2, 7, Holidays!A:A) // weekend = Friday-Saturday

Note that NETWORKDAYS counts both the start and end dates, unlike most programming conventions.

Fill the holiday range automatically (Google Sheets)

=IMPORTDATA("https://bankday.jacklehoff4866.workers.dev/v1/business-days?calendar=us-fed&start=2026-01-01&end=2026-12-31&api_key=YOUR_KEY")

Or skip the holiday range entirely and compute the answer directly:

=IMPORTDATA("https://bankday.jacklehoff4866.workers.dev/v1/business-days/add?calendar=gb&date=2026-12-23&days=3&api_key=YOUR_KEY")

IMPORTDATA returns the JSON; wrap it with REGEXEXTRACT(…, "\d{4}-\d{2}-\d{2}") to pull out a single date.