Hello, this is Matsubara, CRM Evangelist.

"For now, we're managing fine with Excel."
—Many business owners feel this way.
In fact, Excel is an excellent tool, and I have no intention of denying that.
However, as your company grows and your number of clients increases, managing customer data in Excel can unknowingly cause you to lose five important things.

This time, we'll go through those five points one by one.

table of contents

1. The premise is that Excel is not to blame.
2. What is being lost ①: Continuity of relationships
3. What is being lost ②: Speed ​​of response
4. What is being lost ③: Data accuracy
5. What we are losing ④: Information security
6. What is being lost⑤: Analytical skills for business decision-making
7. What happens when 7.5 overlap?
8. Where should I begin?
9. Frequently Asked Questions (FAQ)
10. Summary

1. The premise is that Excel is not to blame.

First, I want to make it clear that there is nothing inherently wrong with Excel as a tool.
It's an excellent spreadsheet program, and it functions perfectly well for small teams and a limited number of business partners.

The problem arises when, as the company grows in size, the number of clients, and the number of employees, it starts to exceed the limits of what Excel, as a spreadsheet tool, can be used for.
BeforeDebunking common misconceptions about CRMHowever, as mentioned earlier, trying to manage the "standardized data" and "unstandardized data" that CRM should ideally handle using only a single table structure like Excel will inevitably lead to problems somewhere along the line.

2. What is being lost ①: Continuity of relationships

Customer information managed in Excel is often stored deep within the computers or shared folders of specific employees.
The situation where "the relationship with this customer essentially exists only in Person A's mind" is a common pitfall when using Excel for this purpose.

When Person A is transferred or leaves the company, the history of that relationship—past interactions, preferences, past proposals, etc.—is no longer retained in the organization's memory.
The new person in charge will be forced to build relationships from scratch.
Even if the Excel file appears to be carried over on the surface, the "information between the lines" that isn't written there is actually the most valuable part.

3. What's missing (2): Speed ​​of response

When managing customer information using Excel, the person in charge needs to either remember when to contact the customer next, or periodically review the file to confirm this information.

- The timing of follow-up depends on the person in charge's memory.
- Multiple users attempting to update the same Excel file can result in overwrites or conflicts.
- It's not possible to instantly see a list of which projects are currently underway and which are stalled.

These issues directly lead to missed opportunities and missed responses.
BeforeLoss simulation if CRM is not implementedAs mentioned earlier, failure to address issues results in accumulating losses that can be measured in concrete amounts.

4. What is being lost ③: Data accuracy

Excel does not have a built-in mechanism to enforce input rules.
Therefore, the following variations in notation will inevitably occur over time.

- Variations in spelling such as "〇〇 Corporation", "(Co., Ltd.) 〇〇", and "〇〇 Corporation".
- Presence or absence of hyphens in phone numbers, and a mix of full-width and half-width characters.
- Duplicate data where the same customer is registered on multiple lines with slightly different names.
- Version control becomes confusing, making it difficult to determine which file is the "latest version."

Such inconsistencies and duplications in notation make it difficult to obtain accurate figures when attempting to aggregate and analyze them later.
The situation where "the data exists, but it cannot be trusted and used" is a common symptom of the final stages of Excel usage.

5. What we are losing ④: Information security

This is a point that is often overlooked.
Managing customer information using Excel files presents structural risks such as weak password protection, widespread file copying, and failure to collect information upon employee departure.

According to a survey by Tokyo Shoko Research, 10.5% of personal data leaks and losses reported by listed companies and their subsidiaries in 2025 were caused by "loss or misdisposal."
Even today, seemingly insignificant events like the loss of a laptop or USB memory stick can still lead to serious data breaches.
For further information, please read Risks of managing customer information in Excelis explained.

6. What is being lost⑤: Analytical skills for business decision-making

As management increasingly relies on Excel, it becomes difficult for executives and managers to grasp in real time the overall state of the company's relationships with customers.

- Each time a report is submitted, the person in charge needs to recompile the Excel file individually.
- It takes time for the results to be compiled, and the situation may change during that time.
- We are forced to rely on subjective reports such as "it seems okay somehow" or "I'm a little worried."

The concept of "relational assetization" advocated by CRM 4.0 aims to transform these subjective judgments into judgments based on objective data.
This foundation cannot be created using Excel alone.

7. What happens when five things overlap?

These five "things we're losing" are problems on their own, but in reality, they are intertwined and worsen each other.

When the continuity of relationships is lost, the speed of response slows down.
When the response speed slows down, the person in charge becomes anxious and skips manual data entry, which reduces the accuracy of the data.
When data becomes inaccurate, the analytical capabilities needed for business decision-making are lost.
And if all of these issues accumulate, and then a computer is lost or files are accidentally sent to the wrong person, the last line of defense regarding information security will also crumble.

Using Excel initially seems to present no problems.
However, these cracks will quietly but surely spread as the company grows.

8. Where should I begin?

You don't need to solve everything at once.
I recommend starting with the next step.

1. Inventory how many Excel files currently contain customer information and which computers they are distributed across.
2. Consider migrating your most important customer data (such as customer information and ongoing projects) to a centralized management platform like a CRM.
3. Check if there are migration methods (such as an import function) that allow you to use existing Excel data as is.

For more details , please also see our complete guide to migrating from Excel to CRM .

9. Frequently Asked Questions (FAQ)

Q. Do I need to completely stop using Excel?
No.
There's nothing wrong with using Excel for analysis or simple calculations.
The problem is relying solely on Excel for "managing primary customer information."

Q. Is Excel sufficient when a company is small?
When your business is small and you have few clients, Excel may be perfectly adequate.
However, situations such as "having only one person in charge" or "the number of clients starting to increase" are indicators that you should consider reviewing your system.

Q. How much effort will the migration require?
If there's a mechanism to import existing Excel data, you won't need to re-enter everything from scratch.
By gradually transitioning from the most important items, the burden can be reduced.

Q. Of the five things you've lost, which one should you prioritize addressing?
Depending on your company's situation, in many cases, starting with "relationship continuity" (issues with handover when personnel change) naturally raises awareness of other issues as well.

10. Summary

Managing customer relationships in Excel can unknowingly lead to the loss of five key elements: the continuity of relationships, the speed of responses, data accuracy, information security, and the analytical power needed for business decision-making.
It's not Excel's fault.
This means the company has grown beyond the size that can be managed with Excel.
If you have even the slightest idea of ​​what might be causing this, start by taking stock of your current situation.

EMOROCO CRM Lite costs ¥1,500 per user per month (minimum 3 users) and has no initial setup fee, with a 30-day free trial.https://www.emoroco.com/You can start from there.
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Additionally, we publish useful articles about CRM 4.0 on note ( https://note.com/arcuss_crm ), so please check them out as well.

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