An Inside Look at Copilot in Excel
When you ask Copilot in Excel to “add a drop-down menu to this column” or “fix this formula in the team inventory tracker,” behind the scenes, Copilot reasons about your intent, picks and applies the right Excel features, and then edits the workbook. This can feel straight forward for some tasks but, now imagine you’re a Finance professional asking Copilot in Excel: “What’s broken in this valuation model, and how does fixing it change the outcome?” This is not a simple single formula request; it is an end-to-end finance workflow. To tackle it, Copilot needs to inspect the workbook, understand the finance specific business question, identify assumptions and formulas that may be wrong, correct the model, recalculate outputs, and explain the impact in a way a finance professional can trust. A good answer is not just “here is the new result.” A good answer is a clear, auditable explanation of what changed, why it changed, and its impact on values in the model. That kind of prompt is what we think of as an L4 workflow: an open-ended business problem that requires multiple steps, multiple Excel capabilities, and domain judgment. It is also a great way to understand why evals matter. To provide a great response to this question, many different operations and features need to ladder together successfully to deliver the final result. So how do we make sure every part comes together to solve the customer's intent? This is the job of our evaluation system, aka our "evals.” We’ll provide a brief tour through how we think about evals in Excel: what they are, how we organize them, the benchmarks they produce, and how we use these results to make Copilot in Excel better every week. What are evals, and why do we have them? An eval is a repeatable test of Copilot quality. We give Copilot in Excel a task and a starting workbook, let it do its work, and then grade the output against a series of checks and rubrics. These checks go beyond just confirming whether a value is correct. They also assess whether the workbook is usable, auditable, well- formatted, and aligns to Excel best practices. We evaluate more than the final workbook output. For agentic workflows, the path to the result matters too: what steps the agent took, which tools it called, how many turns it needed, how long the experience took end to end, and more. Looking at that trajectory helps give us a clearer measurement of whether the agent is becoming more accurate, capable, and efficient at how it reaches the desired result. Evals measure Copilot quality and are how we move from “this feels better” to “this is measurably better.” A prompt tweak, model upgrade, or a new tool can improve one customer intents while quietly making another worse. Our evals help us catch those regressions before they reach customers, as well as quantify improvements from new capabilities and find quality gaps early enough to prioritize fixes. How we organize our evals Excel is used by millions to complete a wide range of work: tracking lists, analyzing sales, managing operations, building financial models, planning budgets, and much more. Even the same task can have different expected answers whether you’re a finance professional or a small business owner. To measure Copilot in Excel quality reliably, we ensure our eval cases represent the breadth of customer workflows and all the different flavors of spreadsheets they use. We organize eval cases across several dimensions. Complexity is one of the most important dimensions, because it lets us test the building blocks separately while also testing the full customer workflow. We also categorize cases by customer role, domain, workbook characteristics, Excel feature usage, and more, so our benchmarks reflect the breadth and depth of real Excel work. Complexity: L1 through L4 We think about task complexity as a ladder. At the bottom are atomic actions and individual features. Higher up are multi-step tasks. At the top are open-ended workflows that sound more like business problems. The important point is that an L4 workflow is only as strong as the L1, L2, and L3 capabilities underneath it. L4 workflows: solving an open-ended business problem, such as debugging a valuation model or determining how much cash is available for debt service. L3 multi-step tasks: combining features to complete a defined goal, such as creating a sales summary worksheet or building a cash-flow bridge. L2 feature usage: using an Excel capability correctly, such as creating a PivotTable, applying conditional formatting, building a chart, or using formula auditing. L1 actions: single operations such as inserting a row, editing a formula, formatting a cell, or creating a label. Let’s go back to the valuation example at the start of the blog: “What’s broken in this valuation model, and how does fixing it change the outcome?” Copilot needs to break the work into several major steps: inspect the model structure, locate the key assumptions, audit the formulas, correct the calculation logic, compare the before-and-after outputs, and summarize the business impact. Each step sounds simple at the surface, but each depends on many smaller capabilities working reliably. Level What it means How it shows up in the valuation scenario L4: Workflow Solving an end-to-end business problem “What’s broken in this valuation model, and how does fixing it change the outcome?” L3: Multi-step task Composing multiple Excel capabilities to reach a goal Identify incorrect assumptions Correct formulas Recalculate outputs Quantify the impact L2: Feature usage Using one Excel capability correctly Apply formula auditing Update cross-sheet references Build comparison tables Document changes L1: Action Performing a single atomic operation on the grid Edit a formula Insert a table Format cells, values Write a label and notes Check cell reference Customer role and vertical domain What a good workbook looks like in Excel is often domain-specific. A formula that is acceptable in a general spreadsheet may not meet the bar for a finance model. A summary that works for a small business owner may not be enough for a consultant preparing a client deliverable for a large enterprise. That is why we build and review eval cases with domain-specific expectations in mind. We’ve worked closely with industry partners and customers to validate coverage, review input and output workbooks, and author grading rubrics and success criteria. Through these processes, we ensure our evals are realistic, aligned to expert human judgement, and reflect their taste and domain specific expertise. For example, we look at the shape of the workbook itself: number of sheets, workbook size, data density, formulas, tables, charts, and other Excel features. Real workbooks are rarely tidy single-tab examples. They can be large, messy, and full of context. Another example is our finance-specific rubrics for model structure, formula construction, auditability, and presentation quality. From categories to benchmarks Once we have categorized our eval cases, we curate them into benchmarks. Our goal here isn’t a single benchmark or a single number. Rather, we have different benchmarks for the different types of decisions we face while building Copilot in Excel. Some of our benchmarks provide broad coverage with an emphasis on comparability. Others target Excel-specific behaviors and customer workflows for specific feature areas or customer segments. Here is a subset of the benchmarks we use internally: Public benchmarks One public benchmark used by many spreadsheet products is SpreadsheetBench, a benchmark of spreadsheet tasks that provides broad coverage of common operations. Internally, we’ve further curated and validated subsets of this benchmark to adjust ambiguous queries, improve grader correctness, and improve signal to make results more easily applicable. However, we believe our internal benchmarks better reflect the type of work and expectations of Excel customers. Private benchmarks In addition to public benchmarks we maintain several internal benchmarks within the Excel team. Some examples include: RegressionBench helps us detect whether a change has broken something that used to work. CustomerBench focuses on matching production customer distributions across task complexity, domains, workbook shapes, and other dimensions. This provides an signal that mirrors customer usage. OfficeJSBench measures whether the operations Copilot generates to act on the workbook execute reliably and produce the intended result. FinanceBench is one of our deep and challenging vertical benchmarks focused on finance workflows and uses finance-specific rubrics for correctness, structure, and auditability. We developed FinanceBench with input and review from partners like Financial Modeling Institute (FMI), Microsoft Finance, and other finance professionals and customers. The collection of these benchmarks provides both broad and granular measurements on quality. They allow us to measure where the agent is strong, where it can improve, and whether a change has the intended impact on the customer experience. How eval results make Copilot in Excel better Evals are not just a reporting mechanism - they are deeply integrated into how we build the AI experience in Excel. Eval benchmarks help: Gate releases: Benchmark runs are part of how we decide whether a feature is ready to advance from our validation environments to customer availability. If evals detect issues or the improvement doesn’t show intend impact, the change does not move forward. Improve based on customer signals: When a customer conversation or signal reveals opportunity for improvement, we classify it and then create representative eval cases for it. We can then fix it and measure improvement in subsequent eval runs. Model training: We use rubrics and graders from evals to provide signal to tune models for spreadsheet work. Inform the right model for the job: Comparable benchmark results help us route tasks to models that balance quality, latency, and capability, to provide the best experience to customers. Over time, this creates a virtuous cycle: feedback and usage identify opportunities, evals quantify them, fixes and training address them, benchmarks confirm the win, and the next release starts from a higher bar. Why the hero scenario matters Coming back to the valuation prompt, the reason it matters is that it represents the kind of work people increasingly want Copilot in Excel to help with. They do not just want help inserting a chart or writing one formula. They want help completing meaningful work: understanding a model, finding an issue, improving the analysis, and making the result easier to trust. We can only deliver that L4 experience if the underlying layers are strong. Formula edits have to be correct, feature usage has to be reliable, multi-step plans have to stay coherent, and the final workbook has to be clear, complete, and auditable. That is why our eval system measures both the broad set of things people do in Excel and the deep workflows that matter most in demanding domains like finance.What’s New in Microsoft 365 Copilot | May 2026
Welcome to the May 2026 edition of What's New in Microsoft 365 Copilot! Every month, we highlight new features and enhancements to keep Microsoft 365 admins up to date with Copilot features that help your users be more productive and efficient in the apps they use every day.
Where does Copilot actually fit in your Excel workflow?
I’ve been experimenting with Microsoft 365 Copilot for some of my Excel-related work, especially for quick analysis, formula generation, and summarizing data. Right now, I’m mainly using it for first-pass exploration (like generating formulas or getting quick insights), and then switching to native Excel features like PivotTables, Power Query, or structured formulas when I need more accuracy or repeatability. What I’m struggling with is knowing when it actually makes sense to use Copilot vs just sticking with Excel’s built-in tools. In your experience, where does Copilot genuinely add value in a production workflow, and where does it still fall short compared to traditional Excel tools? Are there other ways you’re using it that I might be missing?
Copilot in Excel - Web vs Desktop
Hello Community! Over the past few months, I've noticed that when using Copilot in Excel, the newest features appear in Excel on Web for weeks or months (also PowerPoint, and possibly Word and other M365 Applications) before appearing in Excel on Desktop App. Right now, this is occurring with Plan mode appearing in Excel Web although not Excel Desktop. Does anyone know why this occurs?
Pivot Table
Hi everyone, I have an issue with the pivot table. There are filters from slicers and row labels in the table; when I double-click on any category from the table to see the filtered data, Excel fetches all data, not just what I filter on. Like below, I filtered from the slicer, and from the row labels, (Bills) should be between 100,000 and 200,000. I would like to see the (Bills) for (Central) in the (Start), but it gives me 632,478 and bills less than 100,000 and 200,000, not the 3 clients. Even if I tried from (In Progress), it's the same; it brings all data. The issue is only with the Bills column, but other filters come up correctlyNew ways to customize how Copilot edits your workbooks
If you’ve ever typed the same formatting and style instructions into your Copilot prompt every single time - don’t merge cells,” “use my header style,” “name the tables this way”- we built two new features for you! These new customization options let you set your rules once and have Copilot follow them automatically. Personalization is now generally available, and workbook rules are rolling out to general availability across Excel for Web, Windows, and Mac. Personalization: your rules that follow you Personalization lets you tell Copilot your standing preferences once, and it follows them across every workbook you touch. No more repeating yourself. Copilot learns your preferences before it starts editing, so the output always reflects the guidance you provide. Set preferences for things like: Formatting: “Never merge cells.” “Don’t use red in charts.” “Always format currency in USD with no decimals.” Naming conventions: “Name tables with a tbl prefix.” “Use clear, descriptive sheet names.” Formulas: “Write formulas with structured table references, not cell ranges.” PivotTables & report styles: “Default to my standard summary layout with bold headers and subtotals.” How to access it Open Copilot in Excel. Open Settings (...) → Personalization. Add your preferences in natural language and save. Copilot applies them every time you prompt it. Workbook rules: standards that follow the workbook Where Personalization is about you, workbook rules are about a specific workbook. Rules live in the workbook and travel with it when you share it, so teams and organizations can standardize how a file should look and behave, and everyone who uses Copilot to edit it stays consistent. These rules are stored in the workbook as a sheet with the “.Rules” naming convention, which signals to Copilot that they should be followed for all edits made in the workbook, regardless of the user. What makes workbook rules especially powerful is the ability to tap into Excel’s calculation engine, giving you a low-barrier way to leverage the Excel functionality you already know how to use. Unique ways to leverage workbook rules: Point to an exact example: Format a sample range exactly how you want it, then tell Copilot “match this formatting”—an exact example beats a written description. Make rules dynamic with formulas: Reference cells, ranges, or other sheets so rules can change based on what’s already in the workbook. For example, applying one instruction when a project is over budget and another when it is on track. Use Copilot to build and edit the rules sheet: Start from a blank .Rules sheet or an existing template, then ask Copilot to draft, refine, or update the rules. Aim it at an existing, well-built example sheet and ask it to infer the rules automatically for a fast way to standardize an established template. Share for consistency: Because the rules are stored in the workbook, every collaborator and every future version stays on-standard. Share rules sheets with others to bring into their own workbooks for consistency. How to access it Open Copilot in Excel. Open + → Create workbook rules. This creates a new template. Add rules in plain language, point to an example range, or ask Copilot to generate rules from a sample sheet. Rules must be in column A of the sheet, but can reference other areas of the sheet (e.g. example of a formatted table of range). Note: If you have an existing sheet you'd like to leverage, simply rename the sheet with ".Rules" and start adding your rules in column A. Try it today: Personalization is available to all Copilot in Excel users on Excel for Web, Windows, and Mac. Learn more about Copilot in Excel personalization. Workbook rules is available in the Insiders channel for Windows and Mac and rolling out to general availability in the coming weeks. Learn more about Copilot in Excel workbook rules.
Sheet View Issues with Excel Web Browser
Hi, I have created a Excel document for my department to use, I tried Excel App but due to the size of the Spreadsheet it kept freezing, as a result I switched it to use Excel through Web Browser. The sheet no longer freezes which is good. I do have another issue though.....I wanted multiple users to be able to access, edit the sheet at the same time so I did some research and Sheet View seemed to be the way forward. I created a Sheet view for each employee to use so when you go to View, Sheet View and click on the relevant person their work is updated, saved etc and this shouldn't affect others view. This is working in terms of people editing. The main issue now though is that despite following advice sometimes when someone changes a filter on their own sheet view it seems to change others view. My understanding was you can hide, filter etc within your own Sheet view but this doesn't seem to be the case.......PLEASE HELP!!!! My excel and computer Skills aren't excellent to please any simple advise would be great.
