B4fx =PRESENT("Using AI in Excel", verify_everything:=TRUE)

ABCDEFGHI

B4:H7

Using AI in Excel

From Copilot chat to add-ins — getting real work done, and knowing when to =VERIFY() the machine's work.

Training SessionJULY 2026 · 001 / 018

S2fx =AGENDA(6)

On the worksheet today

What we'll cover

01Free Copilot chat as a "syntax helper"

02Natural language → working formulas

03Where AI struggles: tables & hallucination

04Add-ins (Claude, ChatGPT) vs Copilot

05AI can build your PowerPoint deck too

06The golden rule: verify everything

Overview002 / 018

S3fx =IF(built_into_365, "Copilot", "Add-in")

First, some vocabulary

Two different things people call "AI in Excel"

A1

Built in

Copilot

Microsoft's own assistant, baked into the Microsoft 365 environment. It's part of the house.

B1

Bolted on

Add-ins

Third-party tools you install into Excel — Claude, ChatGPT and others. External software, invited in.

They work differently — and it matters.

Overview003 / 018

S4fx =TRANSLATE("plain English", "Excel syntax")

Part one · The syntax helper

You don't need a paid licence
to get formula help

The free Copilot chat — in the browser or the Windows app — acts as a translator from plain English into Excel syntax.

You write the formula. It tells you how.

Copilot Chat004 / 018

S5fx =TEXTJOIN(" ", TRUE, A2, B2)

Example 01 · Joining text

Ask in English, get the syntax

"Join the text in these two cells into one cell"

=A2&" "&B2
=TEXTJOIN(" ", TRUE, A2, B2)

It gives you the tool and the reasoning — not just something to paste.

Copilot Chat005 / 018

S6fx =VLOOKUP(the_why, patient_tutor, 4, FALSE)

Example 02 · Learning, not just doing

A patient tutor for broken formulas

"Explain why my VLOOKUP isn't working — and teach me"

Match type

Exact vs approximate match — the fourth argument most people never set.

Column index

Counting to the wrong column in the lookup range.

First column

The lookup value has to live in the first column of the range.

Learn the why, not just the fix.

Copilot Chat006 / 018

S7fx =RANDARRAY(rows, columns, realistic:=TRUE)

Example 03 · Practice data

AI is great at fake data

"Make a synthetic dataset for me to practise sorting and pivot tables"

Region	Rep	Units	Revenue
North	Amara	142	$8,520
South	Ben	98	$5,880
East	Chloe	211	$12,660
West	Dev	167	$10,020

Realistic-but-fake sales, staff, dates and categories — ideal for training.

No privacy risk, and you control the shape of the data.

Copilot Chat007 / 018

S8fx =FLATTEN(your_table) ⚠ structure lost

Part two · The catch

LLMs read text, not grids

A	B
Jan	120
Feb	95
Mar	143

→

Jan120Feb95Mar143

Rows, columns and cell relationships get flattened into a sequence — and can be misread. The very structure that makes it a spreadsheet is what the model handles worst.

The Catch008 / 018

S9fx =PLAUSIBLE(answer) <> CORRECT(answer)

Part two · The catch

Why it hallucinates in Excel tasks

It predicts

It generates plausible text — so it can invent numbers that "look right."

It miscounts

Rows miscounted, columns misaligned, totals fabricated.

It's confident

Even when wrong. Tone is not a reliability signal.

Even the vendors say so: OpenAI's own guidance is that ChatGPT predicts text, not math — every output is a draft until you verify the logic yourself.

The Catch009 / 018

S10fx =VERIFY(everything)

Part two · The golden rule

So — always verify

generate→ explain→ test on a copy→ verify manually→ scale

01Re-run the AI's formula on a small sample you can eyeball

02Cross-check totals and counts manually

03Ask "how did you get that?" and inspect the logic

04Never let AI-reported numbers go into a report unchecked

The Catch010 / 018

S11fx =INSTALL("add-in", from:="Insert › Get Add-ins")

Part three · Add-ins

What is an add-in?

A third-party tool you install into Excel itself, from Insert › Get Add-ins (or Home › Add-ins on newer builds). It appears as a sidebar panel inside your workbook.

Copilot

Baked in. Microsoft's own assistant, part of 365, uses your Microsoft account.

Add-in

Bolted on. External software you install, signed into its own account.

Add-ins011 / 018

S12fx =AVAILABLE(NOW())

Part three · Add-ins

The main add-ins available now

01 Claude — officially launched 7 May 2026 as add-ins for Excel, Word and PowerPoint. Generally available on paid Claude plans, via the Microsoft Marketplace.

02 ChatGPT for Excel — generally available, powered by GPT-5.5, across free and paid tiers (with some regional and plan limits).

03 Aggregators — third-party add-ins (e.g. GPT for Work) let you pick between Claude, GPT and other models in one panel.

Both major AI companies now ship official Excel add-ins.

Add-ins012 / 018

S13fx =SIDEBAR(read_sheet, write_sheet)

Part three · Add-ins

How the Claude / ChatGPT add-ins work

01Install from the Microsoft Marketplace / AppSource, sign in with your AI account

02They open as a sidebar — and can read from and write to the sheet

03Claude reads multi-tab workbooks, understands nested formulas, and gives cell-level citations for its explanations

They can edit your workbook. Be specific about what to update, and double-check what changed so you can revert. They can still mishandle tables and hallucinate — the verify rule doesn't change.

Add-ins013 / 018

S14fx =COMPARE(copilot, add_ins)

Part three · Quick comparison

Copilot vs add-ins

	COPILOT	ADD-INS
Who makes it	Microsoft	Anthropic / OpenAI
How you access it	Built into Microsoft 365	Installed sidebar panel
Model	Microsoft's Copilot models	Claude / GPT-5.5 — same model across apps
Home advantage	Office Scripts, Power Query, Pivot depth	One consistent model in Excel, Word & PowerPoint

The honest trade-off — and neither escapes the "check the work" rule.

Add-ins014 / 018

S15fx =SLIDES(from_your_analysis)

Part four · The payoff

AI can build your PowerPoint deck too

01Claude and ChatGPT both ship PowerPoint add-ins alongside the Excel ones

02Claude works inside your template — your layouts, fonts, colours — and produces native charts you can edit

03Context carries across apps: analyse in Excel, build slides in PowerPoint, draft the report in Word — the AI holds the thread

Excel → Slides015 / 018

S16fx =WORKFLOW(excel → powerpoint)

Part four · A worked example

The Excel-to-PowerPoint workflow

01In Excel, ask the AI to analyse last quarter's data and build charts

02Open your PowerPoint template

03Ask it to create a deck from that same analysis — it pulls the numbers automatically

04Refine slide by slide

It generates a first draft, not a finished deck — check every figure that lands on a slide against the source.

Excel → Slides016 / 018

S17fx =SUM(takeaways)

Wrapping up

Key takeaways

✓

Free Copilot chat is a brilliant syntax tutor — use it to learn the why

✓

AI is great at generating practice data

✓

LLMs are weak with grid-structured data — and hallucinate confidently

✓

Add-ins differ from Copilot: third-party, installed, their own model

✓

AI can build decks from your data — but the draft needs checking

✓

Verify everything before it counts

Takeaways017 / 018

S18fx =PRACTICE(hands_on:=TRUE)

Over to you

Practice / next steps

01Generate a synthetic dataset, then build a pivot table from it

02Ask Copilot to explain one formula you don't understand

03Then deliberately check its answer — practise the verify loop

04If you have an add-in: turn a small analysis into a three-slide deck

=TRUST(BUT_VERIFY)

Practice018 / 018

Using AI in Excel

What we'll cover

Two different things people call "AI in Excel"

Copilot

Add-ins

You don't need a paid licenceto get formula help

Ask in English, get the syntax

A patient tutor for broken formulas

AI is great at fake data

LLMs read text, not grids

Why it hallucinates in Excel tasks

So — always verify

What is an add-in?

The main add-ins available now

How the Claude / ChatGPT add-ins work

Copilot vs add-ins

AI can build your PowerPoint deck too

The Excel-to-PowerPoint workflow

Key takeaways

Practice / next steps

You don't need a paid licence
to get formula help