How to Count Days in Google Sheets: A Practical Guide

Why Day Counts in Google Sheets Matter

If you run a business, agency, or sales team, your life is ruled by hidden clocks: trial periods, renewals, delivery windows, campaign flights, payment terms. Google Sheets is where many of those clocks live. Being able to count days precisely—between any two dates, or between today and a deadline—turns a static sheet into a live radar for your pipeline and operations.

Below are the most useful ways to count days in Google Sheets, from simple manual formulas to fully automated workflows with an AI computer agent like Simular.

Manual Ways To Count Days in Google Sheets

1. Basic Day Difference With DAYS

Use DAYS when you just need the number of days between two dates.

1. Put your start date in cell A2 (for example, 1/1/2025).
2. Put your end date in cell B2 (for example, 1/31/2025).
3. In C2, enter:
   =DAYS(B2, A2)
4. Press Enter. Google Sheets returns the number of days between the two dates (including leap days automatically).
5. Drag the fill handle down to apply the formula to other rows.

Pros

• Very simple, readable syntax.
• Handles leap years correctly.
• Perfect for duration columns on project or deal tables.

Cons

• Only returns days (no months or years).
• Requires manual setup and copying whenever you add new rows.

2. Flexible Differences With DATEDIF

Use DATEDIF when you might need more than just days—like months or years.

1. Start date in A2, end date in B2.
2. In C2, enter:
   =DATEDIF(A2, B2, "D") (for days)
   You can also use "M" for months or "Y" for years.
3. Press Enter, then drag down.

Pros

• Supports multiple units (days, months, years).
• Great for age of deals, contracts, or inventory.

Cons

• Less discoverable (it doesn’t show in the formula helper by default).
• Slightly more cryptic syntax.

3. Working Days Only With NETWORKDAYS or NETWORKDAYS.INTL

If you care about business days (excluding weekends and holidays), use NETWORKDAYS or NETWORKDAYS.INTL.

1. Start date in A2, end date in B2.
2. Optional holiday list in, say, H2:H10.
3. In C2, enter:
   =NETWORKDAYS(A2, B2, H2:H10)
4. Press Enter.

For custom weekends (e.g., only Sunday off), use NETWORKDAYS.INTL:

=NETWORKDAYS.INTL(A2, B2, "0000010", H2:H10)

Here the seven-digit string defines weekends (1 = weekend, 0 = workday).

Pros

• Perfect for project planning and SLAs.
• Automatically excludes weekends and specified holidays.

Cons

• Weekend patterns and codes are easy to misconfigure.
• Holiday ranges must be maintained manually.

4. Quick Subtraction for Simple Cases

Because Google Sheets stores dates as numbers, you can subtract them directly.

1. Start date in A2, end date in B2.
2. In C2, enter:
   =B2 - A2
3. Format C2 as Number if needed.

Pros

• Fast and intuitive.
• Good for quick checks.

Cons

• Less explicit than DAYS, so formulas are harder to read later.
• No built-in handling for workdays or holidays.

5. Days Until Deadline With TODAY()

To build a live countdown to a deadline:

1. Deadlines in column B (e.g., B2).
2. In C2, enter:
   =DAYS(B2, TODAY())
3. Drag the formula down.

Now every time you open the sheet, column C updates automatically, showing how many days remain to each deadline.

Pros

• Great for dashboards and priority views.
• Automatically updates without manual refresh.

Cons

• Still requires you to keep adding formulas for new rows.
• Fragile if someone overwrites the formula.

Scaling Day Counts With Automation and an AI Agent

Manual formulas work when you have one sheet and a few dozen rows. But agencies, RevOps teams, and founders quickly hit problems:

• New deals and tasks keep arriving.
• Each client wants a slightly different calendar logic.
• People accidentally overwrite formulas.
• You waste time debugging instead of selling or building.

This is where delegating to an AI computer agent like Simular Pro becomes powerful.

6. Array Formulas for Semi-Automation

Before we bring in an AI agent, you can already make Sheets more self-maintaining.

For example, if start dates are in A2:A and end dates in B2:B, use:

=ARRAYFORMULA(IF(A2:A="",,DAYS(B2:B, A2:A)))

This single formula in C2 will automatically calculate day counts for every filled row.

Pros

• No need to drag formulas down manually.
• New rows get calculated instantly.

Cons

• Array formulas can be intimidating and hard to edit.
• Still requires you to design and maintain the sheet logic.

7. Fully Delegated Workflows With a Simular AI Agent

Now imagine your Google Sheets are part of a bigger workflow: CRM exports, ad platform reports, project tools, and finance apps. A Simular AI computer agent can behave like a meticulous operations assistant who handles the entire routine around day calculations.

A Simular Pro agent can:

• Open your Google Sheet in the browser.
• Insert the right DAYS, DATEDIF, or NETWORKDAYS formulas based on your instructions.
• Convert raw text into proper date formats before calculating.
• Copy formulas down thousands of rows.
• Cross-check counts against expected ranges (e.g., “no contract should exceed 365 days”).
• Repeat the process daily or on demand via a webhook from your existing systems.

Because Simular is designed to automate nearly anything a human can do on a computer—with production-grade reliability and transparent execution—you can watch every step, tweak the workflow, and then let it run.

Pros

• Scales to thousands or millions of steps without fatigue.
• Works across desktop, browser, and cloud apps, not just Sheets.
• Transparent logs: every click and formula is inspectable.
• Frees you and your team from repetitive spreadsheet maintenance.

Cons

• Requires a short onboarding period to define the workflow.
• Overkill for tiny, one-off sheets with a handful of rows.

8. When To Move From Manual to Agent-Driven

You’ll feel the tipping point when:

• You maintain multiple similar Google Sheets for different clients.
• Your team updates date ranges daily or weekly.
• Mistakes in timing are expensive (late launches, missed renewals).
• You’re spending more time maintaining formulas than acting on insights.

At that point, counting days in Google Sheets is no longer a “quick formula task”—it’s a workflow. That’s exactly the kind of work an AI agent is meant to take over, so you can zoom out and focus on strategy while your digital teammate keeps every clock in your business running on time.