GPT‑5 is now live across ChatGPT—and it’s free by default. The release centers on agent‑like reasoning, fewer hallucinations, richer memory, and personalizable behavior, positioning ChatGPT to understand context, adapt tone, and execute tasks more reliably.
What’s new in GPT‑5
- Agent‑style reasoning Interprets intent, decomposes layered prompts, and performs structured actions.
- Reliability and honesty Lower hallucination rates; acknowledges uncertainty instead of over‑promising.
- Personalization Tune tone and attitude; select from predefined personalities or set preferences.
- Real‑world utility Voice Mode with near‑human cadence; Google integrations for email, calendar, and contacts.
Hallucination and health behavior
- Overall hallucination rates: GPT‑5 Thinking at 4.8%; GPT‑4o at 20.6%; o3 at 22%.
- On HealthBench, GPT‑5 hallucinated 1.6% of the time and flags concerns without overstepping.
Benchmarks and performance
| Benchmark (domain) | GPT‑5 Score | Notable Competitor (Score) |
|---|---|---|
| GPQA Diamond (PhD‑level science) | 89.4% | Claude Opus 4.1 (80.9%) |
| SWE‑bench Verified (code) | 74.9% | Claude Opus 4.1 (74.5%) |
| Humanity’s Last Exam (tools mode) | 42% | Grok 4 Heavy (44.4%) |
GPT‑5 slightly trails on some agentic, tool‑based tasks (e.g., airline flows) but leads in knowledge‑heavy and coding evaluations.
Personalities and voice
- Personalities: Cynic (sarcastic), Listener (empathetic), Nerd (curious, fact‑focused), Robot (objective, task‑oriented).
- Voice Mode upgrades bring fluid, natural speech with controllable tone and pacing.
- Plus: near‑unlimited voice usage; Free: a few hours per day.
- Standard Voice Mode sunsets in 30 days.
- Custom GPTs now speak using your chosen voice profile.
Google workspace boosts (Pro)
- Connect Gmail, Calendar, and Contacts to:
- Draft replies that reflect your prior threads.
- Auto‑check availability and propose times.
- Pull and organize contact info.
- Suggest next actions from ongoing email chains.
- Access remains limited to what’s necessary and only when helpful.
Plans, access, and developer options
| Offering | What you get |
|---|---|
| Free (default) | GPT‑5 core capabilities, personalities, limited Voice, auto model routing |
| Pro ($200/mo) | Unlimited use, GPT‑5 Pro, GPT‑5 Thinking, expanded Voice, Google integrations |
| Model sizes | gpt‑5 (full), gpt‑5‑mini, gpt‑5‑nano (API only) |
| API pricing (example) | gpt‑5 at $1.25 per million input tokens and $10 per million output tokens |
| Dev controls | Adjustable verbosity for concise vs. detailed responses |
Quick use cases
- “Vibe code” your concept into functional HTML/CSS/JS in seconds, then refine layout and interactions.
- Summarize inbox threads and draft responses that match your tone.
- Plan meetings around your real schedule constraints with proactive suggestions.
- Blend personalities with Voice Mode for coaching, strategy sessions, or rapid stand‑ups.
