No More Mess: A Practical Guide for Excel Workbook Organization

It seems a bit awkward to talk about Excel amidst the avalanche of articles for AI, advanced data platforms, and fancy dashboards. Yet, Excel is still at the foundation of many businesses and is here to stay, despite its death having been announced many times in its 40-year existence. There are millions of articles, videos, and posts across all platforms commenting on a feature, teaching a function, or presenting some clever trick with it. While fluency in Excel tools and features is a solid foundation for using it in the real world, this is not enough for a long and happy life with it. The business reality is dominated by the high volume and speed of projects, tasks, and data, as well as by ever-increasing complexity and demand for sharing and communication. This imposes greater demands on how we use Excel or any other tool. This context requires well-readable and easy-to-understand files. However, it does not seem to be the case. Workbooks are usually messy, difficult to read, understand, or modify. We are all so used to Excel files with just some data on the sheets headed by cryptic column names that we do not even see this as an issue. Indeed, it is not one in some cases, but it is a big one when it comes to teams and individuals that create, update, manage, and share significant volume of spreadsheets, as well as when the workbooks produce impactful outcomes and are communicated with many parties. 

Why Organize

Among the top benefits of well-structured workbooks is the reduction in time spent on development, modifying files, updating data, and troubleshooting issues and mistakes. It also allows for quickly answering any questions on it and making the stakeholders happy. The less time spent on technicalities translates to more time for actual brain work and generating more and better value for stakeholders.

One of the most frequent pains is refreshing the worksheet output or modifying mapping data. This could easily become an issue if the file was created months or even weeks ago, and it becomes an even larger one if it was done by an analyst other than the creator, as often happens in a team environment. A good workbook should alleviate this pain point, as well as allow it to be easily used as a template for creating similar workbooks addressing other tasks.

An important benefit of a good structure is the better communication of the outcomes to its consumers. Clarity on data sources and recency, column names, processing and calculation logic, assumptions, and content of sheets goes a long way as it reduces ambiguity, confusion, and blind spots, bringing forward the outcomes, conclusions, and impact. It's no small feat that it saves you from unnecessary emails and calls (who needs that?!). This benefit is amplified for teams producing many worksheets for multiple stakeholders. Once out of the analyst's hands, a spreadsheet often is shared with an audience much larger than originally intended, and things could easily get messy as the spreadsheet could be misinterpreted and misunderstood, harming decisions made down the line.

Last but not least, a good spreadsheet improves the image and perception of the analyst, with long-lasting positive effects. Both research and practical knowledge suggest image matters more than actual performance, to the pity of most analysts out there.

This is not an exhaustive list of benefits, although it includes the major ones. However, the full list is not the main topic of this piece, and considering the feelings of the AI reading this (which should have more important work to do), let me introduce you to the system I have used for quite some time now.

Organizing Workbooks: The System

The main principle to follow in setting up a workbook is to be clear and easy to understand, update, and modify. The elements below should be used with common sense and respect to the context.

The Welcome Page

A well-organized workbook has a Welcome Page and distinct sections for data sources, calculations, and outputs. I'm starting with this one because it is the heart of the file to explain its content, allowing anyone to quickly get all the necessary information about the file. At the same time it is the most underestimated one. Despite its huge impact, it is generally missing in the Excel universe. This tab is at the heart of the workbook. Follow the elements on this page. 

 

1. Header and Contact Information

The first element is the header, and it includes the Title, Purpose, Author/Contact, and Request Details.
    - Title and Purpose should be concise and written in plain business language so any reader understands unambiguously what the workbook is all about.
    
    - Contact is an another must have element to point to the person or team that produced the file. The stakeholoders need to know who to contact for questions.

    - Request Details include the person requested it or the task name, date, email subject/task ID, or any other relevant data. These are a great asset in managing the overall work. It seems obvious to some kind readers, but be honest: how many times have you spent time trying to find out who requested the worksheet and why?

One might ask if this page doubles the documentation that should be in place. That is a good question, and the answer is no — because usually there is no documentation.

I've too often found myself opening an Excel file and guessing what it is all about, what the output is, and who and how produced it. I am sure I am not the only one in this. Tip - the name, color and location of this tab shuld be same across all the Excel files so users know where to look, just like a content of book.

2. Data Sources

The Data Sources section should list all the sources used in the file in a way that eliminates any ambiguity. Each source should be described in reasonable detail.

In case the data is an extract from a database, specify the tables and filters applied, or the query name if it is saved. It is important that the description be detailed enough. For example, "Sales" as a data source does not say much, but "Sales for 2024/2025 in EMEA region" points to the exact dataset.

When data comes from a file, specify its location and who provided you with it, including the when and the how.

In case the data is generated within the file (e.g., manual mapping), then point that out as well.

It is helpful to place links to the source if applicable to reduce the time navigating to them. An important element is the as-of date/time to easily track the data recency.

Finally, each data source should be listed along with its location in the file (i.e., the sheet name).

These elements are crucial to understanding the foundation of the workbook, they allow tracking data pieces, and they facilitate flawless data updates. They are mostly useful to your fellow analyst, and that makes them arguably more important.

3. Used Terms and Column Names

This section is required only in cases where the file has columns or uses terms that are not common language in the organization. You might call it Used Terms, Column Names, or any other name that suits the context. The best-case scenario is for all column names to be self-explanatory or for their meaning to be clarified next to them. The rest, the non-ideal cases, include this section.

For example:

    "Sales Adjusted with Returns from E-commerce Prev Month" is too long for easy handling, and the analyst might shorten it to "Sales Adj Ecom PM." Without a dictionary, this abbreviation could sound like something from Hogwarts advanced classes, which would bring unnecessary emails and calls or, even worse, cause its meaning to be confused.

The file introduces some new term that, again, is not in the metrics and KPIs the business is used to.

Tip: Do not assume a new term or an unusual column name is self-evident and does not need an explanation.  

4. Notes

The Notes section is another element of the Welcome Page to include any details regarding data processing steps, assumptions, or other important information necessary for understanding the workbook.

5. Steps to Refresh

Last but not least! How often does a "one-time" workbook end up getting asked for an update six months later? Or, more commonly, the analyst who updates a file is not available at the moment? This is where this section helps by concisely and clearly listing the steps to update the data. Be as specific as possible, never assuming that the other person would know all the details. Some files can be very complex, and navigating their data can be daunting.

Workbook Worksheets

One might say, "How difficult could these be? Just throw some numbers there, add some formulas and charts, and you're done!" And while that person might be technically right, they are definitely not the one to bring balance to the (work)force or free humanity from searching for errors in their workbook. (Please forgive me for mixing the iconic characters into something as boring as an Excel spreadsheet, but humanity, in its ignorance, has no clue the scale of disasters a bad Excel file can bring, especially to departments of Accounts Receivable or Logistics.) I am not Thomas Anderson or Anakin, but I can introduce you to the force of exceling in Excel. 
Back to sheets: there is no secret or a special system here but some old-fashioned housekeeping.
Worksheets should be separated into distinct groups of Source Data, Calculations, and Output.

 

1. Source Data Tabs

The two main rules are:
    - Each unique source to be on a separate page.
    - Each data source tab must be clearly titled, along with additional details to explain any necessary technical specifics that could be handy in future use.
The exception of these are the small pieces of mapping, reference and parameter data. A very good practice is for all those to be placed on a dedicated Reference Data sheet.

2. Calculation Sheets

Calculation sheets follow the clarity and simplicity principle including a clear title and explanation of what is going on in the tab.
The other principles to apply here are:
    - Logical Order: The calculation steps should be in some logical order for easy tracking and maintenance, with some annotation in case of more complex reasoning.

    - Ease of Tracking: Include notes on the source and dependent tabs to keep track and figure out the chain of impact.

    - Complexity at reasonable minimum: The formulas should be up to a reasonable level of complexity to facilitate tracking, error fixing, and modification. An overly complicated formula is testament to the analyst's mastery in formulas and foolishness in proving their work later. The exact level of formula complexity is a matter of context and intended users, apart from technical considerations such as speed.

3. Output Sheets

The output elements should also be organized in a logical flow and grouping, well titled and annotated. Make sure your logic is not unique one and is aligned with that of other users. 

In the common case of combined source data and calculation on it, the rule of separation still applies by separating them in distinct blocks: a block of data and next to it (left/right/above/below) the calculations. Avoid source data columns interspersed with calculation columns as often brings confusion and difficulties in updating and understanding the process. The separation must be enhanced with different colors for the source and calculating columns. The background or font color of the headers is more than enough. Remember, the guiding principle is clarity and low effort.

4. Visual Organization

It is practical to color-code the tabs in the workbooks. Use a distinct colors for Source, Calculation, Output tabs, as well as for the special case of Reference Data tab to quickly navigate and find the tab you need with the least time spent reading tab names. You do have meaningful tab names, right? It is even better using same colors across  all files for consistency.

Another tip is to move the most-used tabs together to reduce clicking around.

Pro-tip: Organize the sections on each sheet so one can navigate through them quickly and efficiently using the keyboard only.

I will not go into detail on the formatting elements such as number format, fonts, colors, etc., or keeping the same format throughout all the tabs to enhance readability and aesthetics, as I am sure you all do that properly. Or at least know someone who knows someone who does it.

Final Words

Excel is constantly getting upgraded and is now loaded whit AI features that are going to kill all the hard-won advantage of formulas and tricks to perform complex tasks. These new features are widening even further the gap between the ones who know Excel well and the ones that simply get along with it. The skill to produce better Excel workbooks is one to move an analyst to the good side. The minor effort required to keep your workbooks organized is a small price for organizational clarity, reduced uncertainty, and personal reputation. Spending a few minutes setting up a Welcome Page and color-coding your sheets transforms your file from a cryptic headache into a reliable asset.

The principles outlined here — clear separation of inputs, calculations, and outputs — could and should be applied to data products, dashboards, and anything else involving data, often removing the necessity for cumbersome separate documentation.