OpenAI made this whole market. ChatGPT’s launch in late 2022 turned language models from a research curiosity into a consumer product, and it has been the most used AI tool ever since: Pew Research Center’s February 2026 survey found 44% of US adults using it, and OpenAI has cited over 900 million weekly users. For your firm, that popularity matters before you buy anything, because your people already know it, and some of them already use it for work.
What you are buying
OpenAI sells three different things, and it helps to keep them apart:
- ChatGPT, the app: the chat interface on web and mobile, in free and paid personal tiers, and in Team and Enterprise tiers for organisations. The business tiers are the ones that matter for a firm. They exclude your conversations from model training by default, add workspace administration, and come with terms you can show an auditor.
- The API: the same models, sold per use for building into your own systems. This is what powers custom automations, document pipelines and assistants, and it’s charged per job rather than per seat, which suits automation work.
- The model range: OpenAI offers everything from fast, cheap models to its most capable reasoning models. The names change often enough that chasing them is a mistake. What matters is that the range lets you match cost to task, which any well-built system should do automatically.
The tier decision in one view:
| Tier | Training on your data | Admin controls | Right for |
|---|---|---|---|
| Free / Plus (personal) | Possible; opt-outs are personal settings | None | Private experimentation only |
| Team | Excluded by default | Workspace, seats, sharing | The standard firm starting point |
| Enterprise | Excluded, contractually | Full: SSO, retention, compliance | Larger firms, higher stakes |
| API | Excluded on business terms | Per-key, per-system | Automations and custom builds |
What it does well
ChatGPT’s reliable wins are the everyday ones:
- Drafting. First versions of emails, letters, summaries, meeting notes and internal documents. An hour of writing becomes a few minutes of review.
- Summarising. Long documents, threads and transcripts cut down to what matters, with the original one question away.
- Explaining. Unfamiliar jargon, a regulation, a spreadsheet formula, in plain English, at whatever depth you ask for.
- Structuring. Messy notes turned into clean tables, lists and templates. Voice and image input make capturing them easier still.
None of this replaces judgement, but it does remove a lot of typing.
The equally reliable failure is mistaking fluency for accuracy. ChatGPT will sometimes state something false with complete confidence. The realistic limits guide covers this properly. The short version: anything factual going in front of a client gets checked by a person who can tell.
The data questions
Before client or sensitive data goes anywhere near it, you need:
- A business tier in place, with training exclusion confirmed in writing
- OpenAI’s data processing agreement signed, and its sub-processors noted
- Processing location and retention recorded in your DPIA
- One rule circulated and enforced: client personal data only ever goes in the approved, contracted tool, never in anyone’s personal account
The most common ChatGPT incident in small firms isn’t a vendor failure. It’s a member of staff pasting client information into a free personal account, because nobody named an approved alternative. The approved-tools policy template is the one-page fix, and the UK governance guide shows how it fits with Consumer Duty, SM&CR and UK GDPR.
Where it fits
Choose ChatGPT as your general staff tool when no single office suite dominates how you work, or when you want the biggest ecosystem and the fastest-moving features. If your firm lives in Microsoft 365 or Google Workspace, compare it honestly against Copilot and Gemini, which win by being inside the tools you already use. For judgement-heavy long-form writing, run the same real tasks through Claude before deciding. The overview of AI providers has the three questions that settle the choice.