Excel Show Changes in 2026: See Exactly What Copilot Edits Before You Accept It

Handing Copilot the keys to your workbook used to feel like a leap of faith. You'd type a request, Copilot would rewrite a range of cells, and you'd be left squinting at the grid trying to spot what actually changed. In 2026, Microsoft closed that trust gap with Show Changes, a review layer built on top of Work IQ that highlights exactly which cells Copilot touched, what the values used to be, and why the change was made. If you work with shared models, financial forecasts, or any spreadsheet where a silent edit could cause real damage, this is the update that finally makes AI-assisted Excel safe to use at scale.

What Work IQ Actually Does

Work IQ is the context engine sitting behind Copilot's Excel edits. Instead of guessing at what you mean from the workbook alone, it pulls in relevant context from your emails, meeting notes, Teams chats, and related files so that Copilot's suggestions are grounded in what's actually happening around the spreadsheet.

Ask Copilot to update the Q3 numbers and Work IQ can retrieve the actual Q3 figures from a finance email thread instead of inventing a plausible-looking number. That grounding is the difference between an AI assistant you can trust with real numbers and one you have to double-check line by line.

Show Changes: Your New Safety Net

Show Changes renders every AI-made edit as a visible diff directly in the grid, with colored cell borders marking what was touched, and hovering over a flagged cell reveals a tooltip with the previous value, the new value, and Copilot's reasoning for the change. Nothing is applied silently.

How to review a batch of changes

Open the Edit with Copilot pane from the ribbon or the right-click menu.

Type your request in plain language, for example: update the regional totals using the latest sales export.

Review the Show Changes overlay that appears across the affected range.

Click into individual cells to accept or reject them one at a time, or use Accept All / Reject All for the whole batch.

Confirm the final state of the workbook before saving or sharing it.

Chat vs. Edit: Choosing the Right Mode

Copilot in Excel now has a Chat/Edit switcher at the top of the pane. Chat mode is read-only: ask questions about your data, get explanations, run what-if scenarios in conversation without a single cell changing. Edit mode is where Copilot actually modifies the workbook, and every Edit-mode action automatically routes through Show Changes for review.

Getting into the habit of starting in Chat mode to sanity-check an idea before switching to Edit mode will save you from unnecessary review cycles later.

Step-by-Step Reasoning, Not Just Answers

For multi-step edits, Copilot now exposes its reasoning as a short numbered trail, something like: identified the relevant range, cross-referenced it against the linked email thread, then applied a SUMIFS formula to aggregate the totals. Reading that trail before you accept changes is the fastest way to catch a case where Copilot grounded itself in the wrong source document.

Practical Tips for Using Show Changes Well

Review formula changes as carefully as value changes, since Copilot may swap the underlying logic, not just the result.

Use the Explain This Change tooltip before mass-accepting an entire range.

Pair Show Changes with Excel's version history so you always have a manual rollback path.

For sensitive financial models, reject high-impact cells individually and verify them by hand rather than trusting Accept All.

Ask Copilot to summarize what it changed in plain language after a big edit, useful for handoff notes to teammates.

A Common Scenario: Reconciling a Monthly Forecast

Picture a shared revenue forecast that gets updated every month from three different regional exports. Historically, whoever owned the update would spend an hour manually matching new figures against old ones, hoping nothing got missed. With Show Changes, you can ask Copilot to pull in the latest exports and reconcile the totals, then walk through the overlay in a few minutes: green-bordered cells show new values pulled directly from the source files, and the tooltip on each one tells you which file it came from. Anything that looks off, a number pulled from the wrong region, say, gets rejected individually while the rest of the batch is accepted.

That workflow used to require either total trust in the AI or total distrust of it. Show Changes lets you sit in the middle, which is exactly where most finance and operations teams actually want to be.

How This Fits Into Team Workbooks

Shared workbooks introduce a second layer of trust: not just whether Copilot got this right, but whether teammates will know an AI made this change. Show Changes edits are visually distinct enough that a teammate opening the file later can tell, at a glance, which cells were touched by Copilot versus edited by hand, which matters for audit trails in regulated environments. Pairing this with clear file-naming conventions and a habit of leaving a short note in the workbook after a big AI-assisted update will save your team from the wait, who changed this conversation down the line.

Frequently Asked Questions

Does Show Changes work with Python in Excel?

Yes. When Copilot uses Python to transform or analyze data, the resulting cell changes still route through the same Show Changes review layer, so you're never accepting a Python-driven transformation blind.

Can I turn Show Changes off?

You can choose to Accept All immediately if you're confident in a request, but the review layer itself is a built-in safeguard rather than an optional toggle, which is exactly the point: it's meant to be the default, not an extra step you have to remember.

Make Transparency Part of Your Workflow

Show Changes doesn't just make Copilot safer, it makes it more useful, because you can finally delegate bigger, messier tasks to it without losing your grip on the model. Try it on your next quarterly update: ask Copilot to reconcile a range against a source file, walk through the Show Changes overlay cell by cell, and get comfortable trusting, and verifying, what the AI actually did.