Explain Formulas with Copilot—Now on the Grid
Understanding complex formulas in Excel just got a lot easier. The new Explain Formula feature turns Copilot into your inline assistant, delivering clear, step-by-step breakdowns directly on the grid, right next to your data, no need to switch context or open the chat pane. What makes this especially powerful is that the explanations are contextual, grounded in your actual data and workbook, not generic descriptions. By bringing the explanation to where you’re working, Copilot helps you stay in flow. It’s a seamless, in-the-moment experience that makes it easy to scan, understand, and act on formulas right where you need it most. How It Works Here’s how to get an explanation in just a few clicks: Select a cell with a valid formula A Copilot icon appears next to the cell Click “Explain this formula” from the dropdown Copilot shows a step-by-step explanation directly on the grid Need to dive deeper? Click “Chat with Copilot” to continue the conversation in the side pane Note: If the Copilot chat pane is already open, the explanation will be displayed there instead of on the grid. What It Does: Contextual Formula Explanations When you select a formula cell, Copilot can now explain what that formula does using a dedicated card shown in the grid. Helping you quickly understand what the formula does based on your actual data and context, not just a generic description. This makes it easy to: ✅ Understand the formula’s goal in your workbook ✅ Learn how it works, function by function ✅ Build confidence without ever leaving your sheet For example, given this formula: =I4 * XLOOKUP(H4, $L$4:$L$7, $M$4:$M$7) With just a click, Copilot will explain that: Because the explanation is tailored to your actual data and scenario, it’s faster to grasp, easier to verify, and more relevant to your work. Copilot provides the clarity you need right where you need it. Copilot Can Explain Any Excel formula No matter how simple or complex, Copilot can explain any Excel formula. Whether you're working with math, logic, references, arrays, or text manipulation, Copilot helps you understand what’s going on and why. Availability This feature is gradually rolling out to Excel for Windows and Excel for the web. Feedback We’d love to hear how this new experience is working for you. Let us know: ✔️ Was the explanation clear and easy to understand? ✔️ Was it easy to access the explanation when you needed it? ✔️ Did the overall experience feel intuitive and helpful? Just click the 👍 or 👎 at the bottom of the Copilot response to share your thoughts. Your feedback helps us refine the experience and prioritize what’s next.Building Agent Mode in Excel
Excel is the world’s most trusted canvas for working with data, powering everything from household budgets to Fortune 500 companies, scientific research, operational planning, and classroom learning. It’s where millions turn to think, plan, and build. Agent Mode takes that impact even further, unlocking expert-level capabilities and making advanced analysis, modeling, and automation approachable for everyone, across every domain. Agent Mode lets you describe a task in natural language and then works with you to plan, reason, iterate, and validate the outcome. After introducing Copilot in Excel, it quickly became clear that our users wanted more — richer insights and more direct action on the sheet. Agent Mode aims to deliver on these expectations with a resilient experience that works across domains and data shapes, taking meaningful action directly in your workbook. We’ve developed Agent Mode to take advantage of the full richness of Excel artifacts, including table structures, formula syntax, dynamic arrays, PivotTables, charts, and more. It can create workbooks that are refreshable, auditable, and verifiable. This leap is powered by advances in our reasoning engine and the deeper expression of Excel as a rich modeling language. These breakthroughs allow Agent Mode to not only generate and execute solutions but also evaluate results, fix issues, and repeat the process until the outcome is verified. SpreadsheetBench instructions and obtained an accuracy rate of 57.2%. In our testing environment, Agent Mode makes direct workbook modifications via Excel APIs in a JavaScript runtime. We measure accuracy using the script provided by the SpreadsheetBench authors that grades output using the open-source openpyxl library. For evaluation on Claude and Shortcut.aI, we manually ran the SpreadsheetBench tasks (including answer location information needed for reliable evaluation) and downloaded the Excel files that were produced. These downloaded files were then graded using the same evaluation script provided by the SpreadsheetBench authors. Note that our evaluation with Claude completed on 895 of 912 instructions. Accuracy numbers were calculated using only completed tasks. All OpenAI benchmark results were originally published by OpenAI here. We measure Agent Mode on both our internal evaluation sets and the public SpreadsheetBench benchmark. Our results on SpreadsheetBench place Agent Mode at the leading edge of current systems, accurately completing 57.2% of the benchmark’s tasks. But we want to be clear: we don’t optimize for benchmarks, we optimize for real user jobs in Excel. That means solving messy, ambiguous, and complex tasks that reflect how people actually work. And while SpreadsheetBench is a strong signal, it doesn’t capture everything that makes Excel powerful — like dynamic arrays, PivotTables, charts, and formatting — or the customer need for refreshable, auditable, and verifiable solutions. That’s why we have also developed internal evaluation sets, AI grading, and user feedback loops to guide improvements. We also acknowledge that we have plenty of room for improvement, particularly around things like formatting and presentation-worthy layouts. But we believe our foundation is strong, and the direction is clear: Agent Mode is here to make Excel more powerful, more intuitive, and more helpful than ever before. Designing an Intelligent Spreadsheet Agent At the center of Agent Mode is a reasoning and reflection loop — powered by the latest generation of advanced reasoning models — that can interact directly with Excel workbooks. Rather than jumping straight into action, our system generates model-ready context from a given workbook and leverages an advanced reasoning model to begin planning for a given task. The system then interacts with the workbook by writing and executing code to carry out that plan, reflecting on the results, and evaluating whether the outcome matches the intent. If gaps remain, the loop continues: revising the strategy, pulling in additional context, and exploring alternative approaches. This cycle of planning, execution, and reflection continues until the system determines the task is complete. By combining planning with reactivity, the agent can chart a path, adjust when needed, and ultimately deliver solutions that feel intentional and well thought out. The reasoning engine of our system architecture is model-agnostic by design, allowing for rapid integration of new models as they become available. Loose coupling between our reasoning and workbook interaction layers allow us to quickly swap in and evaluate new models. Managing spreadsheet context Excel workbooks are living systems. They're often large, constantly changing, and filled with rich objects like PivotTables, slicers, and charts. For an agent, trying to absorb every detail all at once is simply impractical. Passing the entire dataset into context, along with the metadata for every object, would overwhelm any current model. Even exposing the thousands of read APIs Excel provides is far too heavy-handed. Instead, the agent approaches the workbook strategically: it pulls in just the pieces of context it needs, when it needs them, navigating the complexity step by step. This makes the agent not just a passive processor of data, but an active explorer of your workbook’s inner workings. To enable this selective exploration, we’ve developed a document context producer that operates within a coordinated push-and-pull system. On the push side, the document context producer proactively sends a compact “blueprint” of the workbook along with the user’s prompt — a summary of spatial layout, values, objects, and the formula dependency graph — encoded as JSON for complex objects and Markdown for tabular data. When deeper inspection is required, the reasoning engine can then request and pull additional information on demand, ensuring it can always operate with the context it needs. This hybrid design balances completeness with efficiency and lays the foundation for future improvements around caching, indexing, and search that will make context retrieval faster and more robust. Engineering domain knowledge of Excel Managing context gives the agent a clear view of the workbook. The next challenge is action: knowing which of Excel’s thousands of functions and APIs to call to get the job done. Excel spans thousands of API controls, including formulas, objects, and advanced features — a surface far too large for any current model to memorize or control directly. Instead of brute-forcing that complexity, we built distilled documentation into our reasoning engine — a compact, structured reference of Excel functions, objects, and specialized tool calls. Agent Mode can draw on this distilled knowledge to execute sophisticated tasks like building PivotTables, charts, slicers, and financial models. By embedding only the essential information, the model gains expert-level fluency in Excel’s internal workings without overwhelming its context window, enabling accurate reasoning across the full feature set of the application. Validation-driven generation In developing and evaluating our core coding and reflection loop, we observed that many spreadsheet errors are silent — formulas return values, but subtle mistakes remain hidden until they cascade into bad analysis. Relying on a single execution step is risky when the goal is trustworthy automation. To counter this, Agent mode in Excel reframes each tool call as an auditable, verifiable workflow. Before executing an action, our reasoning engine first generates lightweight tests to establish expected outcomes. These checks act as verifiable guardrails, ensuring that each step can be inspected and reproduced. Crucially, rather than hardcoding values, Agent Mode carries out all computations directly on the grid. This preserves the full dependency structure of the spreadsheet, allowing users to audit intermediate results, trace formulas, and verify correctness at every stage. Across our quantitative evaluations, we have been able to drive double-digit accuracy improvements with this validation-infused approach. Scaling quality with AI graders As we evolve Agent Mode into a deeply integrated, context-aware companion for data workflows, AI graders have emerged as one of the most critical technical enablers driving quality, trust, and usability. They serve not only as evaluators of accuracy but also as definers of excellence—ensuring that results are not just correct, but also useful, complete, relevant, and delightful. Graders are the mechanism through which we translate abstract quality goals into measurable, actionable standards. In Agent mode, they underpin both offline evaluation pipelines and live user experience metrics, helping us answer key questions like: Did Agent Mode fulfill the user’s intent? Was the output accurate and verifiable? Did the result feel native to Excel? Was the experience satisfying and accessible? Without graders, we would risk optimizing for superficial metrics — like response time or token count—while missing the deeper signals of user success. Looking ahead An early preview of Agent Mode in Excel is available starting today via the Frontier program for Microsoft 365 Copilot licensed customers and Microsoft 365 Personal, Family, or Premium subscribers (under the Microsoft Services Agreement). Agent Mode works in Excel on the web and is coming soon to desktop. To try it, install the Excel Labs add-in and choose Agent Mode (Frontier). Learn more about it in our announcement blog. This preview is just the beginning of our journey. We’re continuing to build a complete, M365 integrated experience that is trustworthy, reliable, and transparent — one that you can depend on for critical work. And from a developer perspective, we’re exploring extensibility solutions that would allow customers and partners to build custom solutions on top of our Agent Mode capabilities. Over the coming weeks and months, we plan to fully integrate and iterate on this experience across all Excel clients. We’ll continue to improve core output quality, refine the Agent Mode interfaces in chat and on the grid, and incorporate user feedback to ensure the experience feels at home in Excel, while unlocking entirely new ways to model, analyze, and automate.Excel Turns 40: Join the Celebration!
This year marks a major milestone—Microsoft Excel turns 40! In honor of four decades of innovation, we’re kicking off “40 Days of Excel”, a global community celebration spotlighting the features that made Excel iconic. It all started on September 30, 1985, when Excel debuted on the Macintosh, introducing a revolutionary graphical interface for spreadsheets. Since then, Excel has evolved into a productivity powerhouse, empowering people and organizations across the globe. Starting today, August 6, we’ll count down to Excel’s birthday with 40 days of features—each one introduced by an Excel MVP or Creator. These passionate experts will share what makes each feature special, offer pro tips, and tell personal stories of how Excel has shaped their work and creativity. This isn’t just a look back—it’s a 40-day journey through Excel’s evolution, packed with nostalgia, insights, and surprises. We invite you to follow along, learn something new, and share your own Excel memories with us. #Excel40 --- Day 1 Let's get started with some favorite keyboard shortcuts—Deb Ashby Day 2 Some favorite number formatting tricks—Leila Gharani Day 3 Save time every single day with Freeze Panes—Grant Day 4 One of the most iconic and enduring features: AutoSum—Bill Jelen aka Mr. Excel Day 5 Some PivotTable tips and tricks—Leila Gharani Day 6 Automate your workflow in seconds with macro recorder—Grant Day 7 VBA and charting—Jon Peltier Day 8 Use Goal Seek to quickly solve for the exact input value needed to reach a desired result—Bill Jelen aka Mr. Excel Day 9 Conditional formatting—John Michaloudis Day 10 Use data validation to help minimize errors in your spreadsheets—Deb Ashby Day 11 Filter by selection—John Michaloudis Day 12 Excel Tables (aka Ctrl-T tables)—by Jon Acampora Day 13 Dynamic charting with Tables—Jon Peltier Day 14 Show trends at a glance with sparklines—Grant Day 15 Reminiscing and reflecting on a favorite feature: Power Query—Oz du Soleil Day 16 Another favorite feature: PowerPivot—Ken Puls Day 17 Filter data using slicers—Aline Day 18 Analyze trends over time using timeline—Sheet Sensei Day 19 Automatically fill your data using Flash Fill when it senses a pattern—Jon Peltier Day 20 AutoSave had me—Leila Gharani Day 21 Instead of tennising emails, just add a threaded comment—Mynda Treacy Day 22 Create your own customized views using Sheet View—Deb Ashby Day 23 See what changes others have made to your workbook using Show Changes—Jon Acampora Day 24 An all time favorite dynamic array function: the FILTER function—Excel Dictionary Day 25 One of Miss Excel's favorite features: XLOOKUP—Miss Excel Day 26 Find UNIQUE values in your data—Aline Day 27 Write your own Excel functions with LET & LAMBDA—Dim Day 28 Dynamic charting with dynamic arrays—Jon Peltier Day 29 One of the coolest Excel features to ever be released: data types—Excel Dictionary Day 30 Automate Excel with Office Scripts—Mark Proctor Day 31 Another Miss Excel's favorite function: GROUPBY—Miss Excel Day 32 All-time favorite text functions: TEXTSPLIT & TEXTJOIN—Excel Dictionary Day 33 One of Miss Excel's favorite hacks: insert pictures into cells—Miss Excel Day 34 Advanced analysis with Python in Excel—Excel Dictionary Day 35 Navigate srpeadsheets with Copilot in Excel — Sheet Sensei Day 36 Think deeper with Copilot in Excel with Python—CheatSheets Day 37 Use Copilot in Excel to clean data—Excel tips for all Day 38 Sentiment analysis using Copilot in Excel—Kevin Stratvert Day 39 Start with Copilot—Piggy Bank Accountant Day 40—Happy Birthday Excel!🎉 COPILOT function—Leila GharaniAdvanced Formula Environment is becoming Excel Labs, a Microsoft Garage Project!
Today, we are thrilled to announce our continued investment in experimentation through the release of Excel Labs, a Microsoft Garage project. Excel Labs is an add-in that allows us to release experimental ideas for you to try, and to give us feedback that helps us evolve Excel to be most useful for you.
