Does Copilot Use ChatGPT?
The Real Model Map, Tier by Tier
Short answer: yes, Copilot runs on OpenAI models (mostly GPT-5.2 in April 2026) with some Claude availability in GitHub Copilot. Long answer: the specific model depends on which Copilot, and the model is not what differentiates them.
The Key Insight: Same Models, Different Packaging
Microsoft licenses OpenAI’s models and wraps them with Work IQ orchestration (which routes queries over your Microsoft Graph data), tenant-bounded security, and Office-app integrations. ChatGPT routes the same GPT-5.2 model through OpenAI’s interface, adding custom GPTs, Advanced Voice, and Deep Research. The AI brain is similar; the interface, data access, and governance model are not.
Model Map: All 10 Tiers (April 2026)
| Product | Model(s) | Context | Reasoning | Images |
|---|---|---|---|---|
| Microsoft Copilot (Free) | GPT-5.2 (web-grounded) | Limited | None | Designer (GPT Image + DALL-E) |
| Copilot Pro | GPT-5.2 priority | Standard | Think Deeper (OpenAI reasoning) | Designer (more boosts) |
| M365 Copilot Business | GPT-5.2 + Work IQ | 128k (Graph-augmented) | Work IQ orchestration | Designer |
| M365 Copilot Enterprise | GPT-5.2 + full Work IQ | 128k+ (Graph-augmented) | Full Work IQ + Purview | Designer |
| GitHub Copilot Pro | GPT-5 default; Claude Sonnet 4.6 selectable | IDE workspace context | Code-specific | N/A (coding tool) |
| GitHub Copilot Pro+ | GPT-5 + Claude Opus 4.6 selectable | IDE workspace context | Code-specific | N/A |
| ChatGPT Free | GPT-5.2 (rate-limited); GPT-4o-mini fallback | ~32k visible | None | Limited |
| ChatGPT Plus | GPT-5.2 priority + o3/o4 selectable | 128k | o3/o4 reasoning models (Deep Research) | GPT Image 1.5 (inline, conversational) |
| ChatGPT Team | GPT-5.2 priority + o3/o4 | 128k | o3/o4 reasoning | GPT Image 1.5 |
| ChatGPT Enterprise | GPT-5.2 priority + o3/o4 | 128k+ (configurable) | o3/o4 reasoning at scale | GPT Image 1.5 |
Reasoning Models: o3/o4 vs Think Deeper
ChatGPT Plus has the clearest advantage in reasoning-heavy tasks. The o3 and o4 models are available to Plus, Team, and Enterprise users and power Deep Research mode, which autonomously browses multiple sources and returns a structured, cited report. Copilot Pro’s Think Deeper uses OpenAI reasoning under the hood but delivers it as extended thinking in a single conversational turn rather than the multi-source, multi-step autonomous browsing of Deep Research.
- + Extended reasoning in a single conversational turn
- + Integrated with M365 Graph context on Business/Enterprise
- - Not autonomous multi-source browsing
- - Fewer explicit citations than ChatGPT Deep Research
- + Autonomous multi-source web browsing (5-30 min)
- + Inline citations with source links
- + Structured report output
- - Takes longer; not suited for quick in-workflow questions
Image Model: DALL-E 3 Is Retired
ChatGPT now uses GPT Image 1.5 for all image generation. This replacement delivers better typography inside images, stronger composition control, and native conversational editing (you can ask it to change specific elements across multiple turns). Copilot Designer uses a Microsoft-integrated version of the GPT Image model family.
When the Model Choice Actually Matters
For 80% of typical office tasks (writing emails, summarising documents, drafting reports, generating images), the model quality difference between Copilot and ChatGPT is negligible. Both use GPT-5.2. Both produce high-quality outputs on everyday tasks.
The remaining 20% where model choice matters: complex multi-step reasoning tasks (advantage: ChatGPT o3/o4), long-context document analysis over 128k tokens (advantage: ChatGPT Enterprise), coding with model selection flexibility (advantage: GitHub Copilot Pro+ with Claude Opus), and M365-specific tasks like meeting summaries using your actual tenant data (advantage: M365 Copilot). In all these cases, the differentiator is the data access and orchestration layer, not the raw model.