ChatGPT, Claude, Gemini and Copilot: what's the difference?

Four names, one kind of tool

ChatGPT is made by OpenAI, Claude by Anthropic, Gemini by Google and Copilot by Microsoft. Each is a general assistant: you type or speak a request, and it drafts, summarises, rewrites, explains or answers. Each runs on a large language model, a program trained on huge amounts of writing to produce likely text. For a reply to a customer, a job ad or a summary of a long email, the four overlap far more than they differ.

Why a ranking would not help

Which one is best changes month to month, as each company updates its models and features. Any list of winners is out of date soon after it is written. A tool that looks slightly better on paper but does not fit how your team works will lose to one that does, so choose on fit rather than on a league table.

The differences that matter to a small business

The first is where it lives. Gemini sits inside Google Workspace, and Copilot sits inside Microsoft 365. If your team already works in one of those, the assistant built into it is close to your email and documents. The second is the business plan and its data terms: is your content used for training, how long is it kept, and what can an administrator control, such as adding people and removing a leaver.

The third is how it feels on your own tasks. Tone, length, how well it follows instructions and how it handles your kind of documents only show up when you try them. Read data terms in the plan's own paperwork, not on a marketing page, and ask for anything unclear in writing.

How to choose

Start with the one that fits the software you already use. Then test two on the same five real tasks: a reply to an unhappy customer, a summary of last week's supplier emails, a job ad, an explanation of an invoice difference, and a step-by-step procedure from rough notes. Give both the same instructions and the same material.

Let the person who will use it daily judge the results, and check the facts in each answer, since a fluent wrong answer looks the same as a right one. Pick the one that needed the least fixing. If two are close, take the one that fits your existing software.

What to do this week

Write down whether your business runs on Google or Microsoft software. Choose the matching assistant and one other, run the five tasks on both, and decide. Then move to a business plan for the people who will use it weekly, rather than leaving everyone on free personal accounts. Add one line to your rules: no passwords, and no private customer information in any tool whose terms you have not read.