WORKDAY vs NETWORKDAYS: two sides of business days
Mirror twins: NETWORKDAYS answers "how many business days between these dates?", WORKDAY answers "what date is N business days from here?". Mixing them up — or forgetting their different inclusivity rules — is where deadline sheets go wrong by a day.
The differences at a glance
| WORKDAY | NETWORKDAYS | |
|---|---|---|
| Question | Date + N working days → what DATE? | Date range → how MANY working days? |
| Returns | A date | A count |
| Includes the start date? | No — day 1 is the NEXT working day | Yes — both endpoints count if they're weekdays |
| Holidays | Optional 3rd-argument range | Same |
| Custom weekends | WORKDAY.INTL (e.g. "0000011" mask) | NETWORKDAYS.INTL, same masks |
| Compatibility | Universal | Universal (executed in every LibreOffice version we test; Excel/Sheets per docs; .INTL variants Excel 2010+) |
Which should you use?
- WORKDAY — Computing due dates: "invoice payable 10 business days after issue" is =WORKDAY(A2,10,holidays). Negative N steps backward — "prep starts 5 working days before the event".
- NETWORKDAYS — Measuring spans: SLA elapsed days, business days remaining in a period, working-day durations between timestamps. Remember it counts BOTH endpoints — the round trip WORKDAY(a, NETWORKDAYS(a,b)) does NOT land on b.
Compatibility (Excel for the web, Sheets & LibreOffice executed; desktop Excel per docs)
Both functions and their .INTL variants execute identically across every LibreOffice version we test; Google Sheets matches in our executed run; desktop Excel behavior matches per Microsoft's documentation — we do not run desktop Excel. The inclusivity asymmetry (NETWORKDAYS counts the start day, WORKDAY doesn't) is identical everywhere too — it's a semantics gotcha, not a compatibility one. Excel for the web is a separate application with its own calculation engine, and that one we do execute: all 8 corpus cases for these functions matched the documented values there (recalculated on OneDrive, 2026-09-01); the per-case values are on the individual function pages.
Example formulas
| Due 10 business days after issue | =WORKDAY(A2,10) |
| Working days between two dates | =NETWORKDAYS(A2,B2) |
| Fri-Sat weekend (e.g. Middle East) | =NETWORKDAYS.INTL(A2,B2,7) |
Full per-version details on each function page: WORKDAY · NETWORKDAYS.