If you sell, manage clients, or run a team, you live and die by timelines: SLAs, campaign dates, onboarding windows, invoice terms. The NETWORKDAYS and NETWORKDAYS.INTL functions in Excel and Google Sheets turn messy calendars into hard numbers: how many working days a deal sat in pipeline, how long support took to resolve, how many billable days a project really consumed.
NETWORKDAYS(start_date, end_date, [holidays]) automatically removes Saturdays, Sundays, and optional holidays. NETWORKDAYS.INTL(start_date, end_date, [weekend], [holidays]) goes further, letting you define custom weekends or non‑standard schedules. Together, they power capacity planning, performance dashboards, and accurate forecasting.
But building and maintaining these calculations across dozens of files is tedious. This is where an AI computer agent changes the game. Instead of you hunting through spreadsheets, the agent can open Excel and Google Sheets, fix broken date ranges, insert the right NETWORKDAYS or NETWORKDAYS.INTL formulas, validate results, and update dashboards on a schedule. You stay focused on strategy while the agent quietly keeps your business-day math clean, consistent, and always up to date.
Let’s start with the basics. Imagine you’re a sales manager tracking how many business days it takes to move a lead from demo to close. You have a start date in column A and a close date in column B. You want the working days (excluding weekends and holidays) in column C.
1.1 Basic NETWORKDAYS in Excel
A2:A100 and end dates in B2:B100.C2, enter: =NETWORKDAYS(A2,B2)Excel counts all working days between the two dates, including both the start and end day, and automatically excludes Saturday and Sunday.
Official docs: https://support.microsoft.com/en-us/office/networkdays-function-48e717bf-a7a3-495f-969e-5005e3eb18e7
1.2 Adding holidays in Excel
H2:H20, each cell containing a valid date (no text dates).C2 to: =NETWORKDAYS(A2,B2,$H$2:$H$20)Now Excel subtracts weekends plus any dates in your holiday range.
1.3 NETWORKDAYS in Google Sheets
Google Sheets works very similarly:
A2:A, end dates in B2:B.C2 type: =NETWORKDAYS(A2,B2)With holidays, assuming H2:H20 is your holiday list:
=NETWORKDAYS(A2,B2,$H$2:$H$20)
Official Sheets reference (NETWORKDAYS and WORKDAY): https://support.google.com/docs/answer/6055612?hl=en
1.4 Custom weekends with NETWORKDAYS.INTL
If your team works a non‑standard week (for example, Sunday–Thursday), use NETWORKDAYS.INTL.
In Excel:
C2, use: =NETWORKDAYS.INTL(A2,B2,7,$H$2:$H$20) Here 7 means Friday & Saturday are weekends.In Google Sheets, the syntax is the same:
=NETWORKDAYS.INTL(A2,B2,7,$H$2:$H$20)
1.5 Avoiding common NETWORKDAYS mistakes
=DATE(2025,1,15)), not strings like "1/15/2025" pasted from CRM exports.$ (e.g. $H$2:$H$20) so they don’t shift when you drag formulas.These manual methods are perfect when you own a single file. But as soon as you’re juggling multiple clients, projects, or funnels, you’ll want automation.
Now imagine you’re running an agency. Every new client gets a project sheet in Google Sheets, and you want business‑day durations calculated automatically the moment a new row appears.
2.1 Automate in Google Sheets with built‑in features and no‑code tools
=ARRAYFORMULA(IF(A2:A="","",NETWORKDAYS(A2:A,B2:B,$H$2:$H$20))) This populates working days for every row with data.NETWORKDAYS exceeds a threshold.
2.2 Automate in Excel with tables, Power Query, and Power Automate
Ctrl+T to create a table.=NETWORKDAYS([@[Start Date]],[@[End Date]],Holidays)Business Days column exceeds SLA.These no‑code patterns remove a lot of manual work, but you’re still the one wiring functions, building flows, and fixing broken formulas. That’s where AI agents step in.
At some point, your operations look like this:
Instead of hiring another analyst, you can delegate this admin to a Simular AI computer agent that uses your desktop, browser, and cloud apps like a human.
3.1 Method 1: Let the agent build and standardize formulas
What it does:
NETWORKDAYS / NETWORKDAYS.INTL formulas.Pros:
Cons:
3.2 Method 2: Agent‑driven reporting and SLA monitoring
What it does:
Pros:
Cons:
3.3 Method 3: Quality‑assurance copilot for date math
What it does:
Pros:
Cons:
By combining solid manual understanding, light no‑code automation, and a Simular AI agent orchestrating the repetitive work across Excel and Google Sheets, you get reliable business‑day metrics at scale without burning human hours on maintenance.
To calculate working days between two dates, you’ll use NETWORKDAYS (or NETWORKDAYS.INTL when you have custom weekends).
In Excel:
=NETWORKDAYS(A2,B2) This returns the number of business days including both start and end date, excluding Saturdays and Sundays.=NETWORKDAYS(A2,B2,$H$2:$H$20)Official guidance: https://support.microsoft.com/en-us/office/networkdays-function-48e717bf-a7a3-495f-969e-5005e3eb18e7
In Google Sheets:
=NETWORKDAYS(A2,B2)=NETWORKDAYS(A2,B2,$H$2:$H$20)For non‑standard weekends (like Friday–Saturday), switch to NETWORKDAYS.INTL with an appropriate weekend code.
When your team doesn’t follow the standard Monday–Friday schedule, use NETWORKDAYS.INTL to define which days are weekends.
In Excel:
=NETWORKDAYS.INTL(A2,B2,7)=NETWORKDAYS.INTL(A2,B2,7,$H$2:$H$20)You can also use a 7‑character string to describe workdays, starting on Monday. "1" means non‑workday, "0" means workday. For example:
"0000011" means Saturday and Sunday are weekends."1000001" means Monday and Sunday are weekends.In Google Sheets: NETWORKDAYS.INTL works the same way. Reuse the weekend codes or strings and optional holiday ranges to mirror your actual shift patterns.
NETWORKDAYS includes both the start date and end date when counting workdays, which often surprises people. For example, if both dates are the same workday, NETWORKDAYS returns 1, not 0.
Common reasons for off‑by‑one issues:
=NETWORKDAYS(A2,B2,$H$2:$H$20)-1NETWORKDAYS(A2,A2,holidays) tells you if A2 is a workday (1) or not (0).Always sanity‑check a few rows by hand: compare NETWORKDAYS to a manual count of workdays on a calendar to confirm your logic.
Holidays are passed to NETWORKDAYS as an optional third argument and should be a range of real date values.
Step‑by‑step in Excel:
Holidays (Formulas > Define Name), or just remember $H$2:$H$20.=NETWORKDAYS(A2,B2,Holidays) or =NETWORKDAYS(A2,B2,$H$2:$H$20)In Google Sheets:
=NETWORKDAYS(A2,B2,$H$2:$H$20)Tips:
An AI agent like Simular can behave like a power assistant who logs into your systems, opens Excel and Google Sheets, and maintains your NETWORKDAYS logic end‑to‑end.
Example workflow:
NETWORKDAYS or NETWORKDAYS.INTL formulas using your regional holiday ranges.Because Simular is a computer‑use agent, every click and formula it applies is transparent and modifiable. You design the workflow once, then delegate the ongoing execution so your team isn’t babysitting spreadsheets every week.