ChatGPT-5 explained: 45% fewer hallucinations, 80% smarter

OpenAI has officially launched ChatGPT-5 — its most powerful, precise, and capable AI model to date.

In an era when AI promises often feel overhyped, ChatGPT-5 is OpenAI’s answer to growing scepticism. The company claims this new version of ChatGPT is not only significantly faster, but also dramatically more accurate than its predecessors.

According to internal tests, ChatGPT-5 is 45% less likely to hallucinate than GPT-4o, and a staggering 80% less prone to factual errors than the earlier GPT-3.5-tier models like OpenAI’s o3.

Let’s break down what makes ChatGPT-5 different — and why it’s being pitched as a PhD-level AI assistant you can actually use.

Accuracy has always been the Achilles' heel of generative AI tools. GPT-4 was smart, but still prone to confidently inventing facts. ChatGPT-5 tightens that gap with what OpenAI calls “refined reasoning,” allowing it to respond faster and with fewer mistakes — particularly in high-stakes use cases like email writing, report generation, and code development.

OpenAI CEO Sam Altman, speaking at a press briefing, even described ChatGPT-5 as a “PhD-level expert” — a big claim, but one the company seems eager to stand behind.

But raw intelligence isn’t the only upgrade here.

ChatGPT-5 also represents a philosophical shift for ChatGPT. The model is intentionally less agreeable, less flattering, and less emoji-happy. That means no more overenthusiastic responses filled with 🎉 and 🙌 — and more direct, to-the-point answers.

Why? OpenAI says users are asking for clarity and confidence, not compliments and cheerleading. So ChatGPT-5 dials down the fluff in favour of efficiency.

In a demo that felt equal parts sci-fi and surreal, Altman used ChatGPT-5 to code an entirely new AI model from scratch — in under five minutes. That’s not a gimmick. ChatGPT-5’s ability to act as a full-stack coding assistant is one of its most hyped features.

Whether you’re building an app, designing a website, or working on a game engine, ChatGPT-5 is positioned as an AI co-pilot that can generate, edit, and even debug code in real-time.

Altman called it ChatGPT-5’s “superpower” — and while that might sound like hyperbole, it’s hard to ignore the implications for developers and startups.

Unlikely — at least for now. When asked if ChatGPT-5 might displace software engineers, Altman pushed back. His take: ChatGPT-5 will increase demand for software by lowering the barrier to creation. In other words, it’s less of a threat and more of a catalyst.

Still, it’s clear that ChatGPT-5 could reshape workflows. From junior devs to tech leads, having a near real-time code assistant changes how teams might operate. It’s not about replacing humans — it’s about amplifying them.

ChatGPT-5 is also being pitched as a smarter AI for health queries. OpenAI says it can now better analyse medical information, flag potential concerns, and even help you understand your test results — a massive leap forward from generic WebMD-style answers.

However, OpenAI is quick to add a disclaimer: ChatGPT-5 does not replace a medical professional. It’s an aid, not a diagnosis tool.

Still, this move suggests OpenAI is eyeing the future of AI-powered healthcare — one where chatbots become essential interfaces for patient understanding, if not medical advice.

In perhaps the most surprising move, ChatGPT-5 is available for free — with some caveats.

Anyone using ChatGPT can now try ChatGPT-5 and its lighter sibling, ChatGPT-5 Mini. Once users hit a certain usage limit, they’ll be temporarily switched to Mini, which is faster, smaller, and still highly capable — kind of like ChatGPT’s lite mode.

For power users, OpenAI has rolled out multiple paid tiers:

• Plus Plan – Higher usage limits than free users.
• Pro Plan – Full access to ChatGPT-5 and ChatGPT-5 Pro, designed for complex, resource-heavy tasks.
• Team / Enterprise / EDU – ChatGPT-5 becomes the default for daily workflows at scale.

Why ChatGPT-5 feels like a turning point