How many spreadsheets is too many?

Question

Hey all. We have some users at our facility that like having alot of spreadsheets open at one time for convenience, however as you can image, performance suffers. We recently updated a Lenovo T14 Gen 1 with 16GB more RAM (24GB total) and I was told it is still lacking in performance. When I checked the PC, I found roughly 10 excel spreadsheets open and then another 4-5 open within websites like sharepoint. I would like to offer a recommendation of "max spreadsheets open" to the users, so I wanted to ask here what you think it would be. I would imagine there is no standard number, and there are other factors such as "are the spreadsheets local or on the company network, or on the internet? How many macros or formulas? etc" that will affect the decision. Do you have a general recommendation for Excel 2019 running on a Lenovo T14 Gen 1 with an Intel Core i5-10210U CPU @ 1.60GHz and 24GB of 3200 RAM and an M.2 SSD Samsung MZVLB256HBHQ-000L7?

Answer 1

Hi @Faas, Jason,

Welcome to the Microsoft Q&A forum.

According to your description, the issue does not come from the RAM but from the CPU. U-series CPUs are designed to be power-efficient, so their performance and multitasking capability can be limited. Therefore, even if you upgrade the RAM, the problem may still occur.

Here are some suggestions for your reference:

• If the Excel files are simple (a few hundred rows, few formulas, and no macros), you can open 8–10 files at the same time.
• If the Excel files are complex, you should open around 4 files.
• For Excel Web, performance also depends on your network condition, since data is processed on the cloud and Microsoft’s servers.

Based on my recommendation, you should use at the same time:

• 4 Excel desktop app files
• 2–3 Excel Web files (depending on your network resources)

I hope this information is helpful.

If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

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Answer 2

Excel has no fixed limit on how many workbooks can be open at once; the practical limit is available memory, CPU, and storage performance.

For modern 64‑bit Office on a device like a T14 with 24 GB RAM and an SSD, performance is typically constrained by:

1. Workbook size and complexity
   • Large models with many formulas, volatile functions, data connections, or macros consume much more memory and CPU per file than small, simple sheets.
   • Shared workbooks with change tracking enabled can grow quickly and open/save more slowly, especially if change history is kept for many days.
2. 32‑bit vs 64‑bit Office
   • 32‑bit Excel is limited to 2 GB of virtual address space per Excel process, shared by Excel, all open workbooks, and add‑ins. Heavy workbooks can hit this limit even if the machine has plenty of RAM.
   • 64‑bit Excel does not impose a hard workbook size limit; it is constrained only by available memory and system resources.
3. Number of Excel instances
   • Multiple large workbooks in a single Excel process share the same 2‑GB limit (if 32‑bit). Opening a second Excel instance can sometimes help distribute memory usage, but each instance still has its own 2‑GB cap.
4. Multi‑session / shared environments
   • In multi‑session environments (for example, Azure Virtual Desktop or Remote Desktop servers), Excel’s multithreaded recalculation is limited to two threads by default to preserve fairness across users, which can make heavy workloads feel slow. On a single local laptop this specific limitation does not apply, but it illustrates that CPU thread availability matters.

Given these factors, a numeric “max spreadsheets open” rule is not meaningful by itself. A better policy is:

1. Base guidance
   • For typical business workbooks (moderate formulas, no huge data models): keep concurrent open workbooks to 10–15 per Excel instance as a soft guideline.
   • For heavy models (large data ranges, complex formulas, Power Query, or macros): keep concurrent open workbooks to 3–5 and close others when not actively used.
2. Check and optimize the environment
   • Prefer 64‑bit Office on machines where users routinely work with large or complex files so Excel can use more memory.
   • Ensure SSD, 8 GB+ RAM, and a multi‑core CPU are in place; your T14 configuration (24 GB RAM, SSD, quad‑core i5) is generally appropriate.
   • Limit or remove unnecessary COM add‑ins, which consume memory within the same Excel process.
3. User practices to improve performance
   • Close workbooks that are not needed for the current task instead of leaving everything open all day.
   • Avoid tracking changes in shared workbooks unless required, as this increases file size and slows open/save.
   • Periodically clean up temporary files and ensure disks are not heavily fragmented (mainly relevant for older systems or non‑SSD storage).
   • For very large or complex models, consider splitting them into smaller, purpose‑specific workbooks.
4. Monitoring approach
   • Use Task Manager or Resource Monitor while users work:
     • If Excel’s memory usage approaches 1.5–2 GB on 32‑bit Office, users should close some workbooks.
     • If CPU is pegged at or near 100% during recalculation, reduce the number of heavy workbooks open concurrently.

In summary, instead of a single hard limit, establish a guideline such as: “For normal files, keep around 10 workbooks open; for large or complex files, keep it to 3–5 and close others,” and pair that with ensuring 64‑bit Office and good hardware, plus monitoring Excel’s memory and CPU usage.

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References:

• Memory usage in the 32-bit edition of Excel 2013 and 2016
• Performance recommendations for Microsoft 365 Apps on Windows 10
• Excel performance: Tips for optimizing performance obstructions
• Excel performance: Performance and limit improvements
• Excel specifications and limits
• Heavy Excel workloads run slowly in multi-session environments