What is GPT-5?
GPT-5 is OpenAI's frontier large language model, released on August 7, 2025 as announced in the official Introducing GPT-5 post. It replaces both GPT-4o and the o-series reasoning line as the default ChatGPT model, combining fast chat responses with extended "thinking" in a single system. GPT-5 accepts text, images, and audio input, and ships a 400,000-token context window with 128,000 tokens of maximum output.
The original August 2025 release was followed by a rapid cadence of successors. GPT-5.2 landed in January 2026, pushing SWE-bench Verified to 80% in Thinking mode per Vellum's benchmark analysis. GPT-5.4 in March 2026 extended the context window to 1.05 million tokens and added a computer-use agentic tier. GPT-5.5 launched on April 23, 2026 at 88.7% on SWE-bench and a claimed 60% hallucination reduction vs GPT-5.4.
OpenAI stated that GPT-5's thinking mode produces 80% fewer factual errors than GPT-4o. Independent reviewer Simon Willison, who had early access at OpenAI's preview event, called GPT-5 "a fast, effective and highly capable model" after running his SVG pelican-on-a-bicycle benchmark. That kind of direct verdict from a skeptical engineer — rather than a marketing claim — is what moved developer consensus.
GPT-5 benchmarks, measured.
Seven headline scores from OpenAI's official launch post and the independent Artificial Analysis GPT-5 report. Every number here is cited — we don't publish anything we can't source.
// scores shown are the highest published result per benchmark for the gpt-5 family through April 2026.
The GPT-5 family, tier by tier.
Seven public tiers shipped between August 2025 and April 2026. Prices are standard-tier per-million-token rates from OpenAI's official API pricing page.
| Model | Released | Context | API Price | Best for |
|---|---|---|---|---|
| gpt-5 | Aug 2025 | 400K | $1.25 in · $10 out | Flagship general model — reasoning, code, multimodal |
| gpt-5 mini | Aug 2025 | 400K | $0.25 in · $2 out | Fast, cheap GPT-5 tier for high-volume workloads |
| gpt-5 nano | Aug 2025 | 400K | $0.05 in · $0.40 out | Edge / classification / autocomplete — lowest cost |
| gpt-5 pro | Sep 2025 | 400K | $15 in · $120 out | Extended reasoning — long chains of thought |
| gpt-5.2 | Jan 2026 | 400K | $1.25 in · $10 out | Refreshed flagship — 80% SWE-bench Verified (Thinking) |
| gpt-5.4 | Mar 2026 | 1.05M | $2 in · $12 out | Long-context + agentic — computer-use benchmark leader |
| gpt-5.5 | Apr 2026 | 1.00M | $5 in · $30 out | Latest tier — 88.7% SWE-bench, 92.4% MMLU |
// sources: openai api docs, the decoder (gpt-5.5)
GPT-5 vs GPT-4o vs o3 vs the frontier.
A straight spec comparison between GPT-5 and the five other frontier-class models available in April 2026. Coding benchmark is SWE-bench Verified. Numbers pulled from OpenAI, Anthropic, Google, xAI, and the LM Council benchmark aggregator.
| Model | MMLU | SWE-bench | Context | $ in / $ out / 1M |
|---|---|---|---|---|
| GPT-5 | 91.4% | 74.9% | 400K | $1.25 / $10 |
| GPT-4o | 88.7% | 33.2% | 128K | $2.50 / $10 |
| o3 | 89.2% | 71.7% | 200K | $2 / $8 |
| Claude Opus 4.6 | 90.8% | 77.2% | 200K | $15 / $75 |
| Gemini 3 Pro | 91.1% | 70.5% | 2M | $1.25 / $10 |
| Grok 4 | 89.4% | 75.0% | 256K | $3 / $15 |
// prices as of apr 2026 · see chatgpt alternatives · grok spec sheet · gpt-5.6 release tracker · claude opus 5 watch-list
What independent reviewers say.
"GPT-5.5 is a sign of the future. What's notable about GPT-5.5 is it demonstrates that rapid AI improvement is continuing."
"GPT-5 is a fast, effective and highly capable model. The pelican SVG took almost four minutes to generate — but the result was the best I've seen from any model."
"The upgrade from GPT-4 to GPT-5 feels like getting a PhD in your pocket — though the real-world reliability still lags the benchmarks on novel, out-of-distribution tasks."
How to use GPT-5 (without ChatGPT Plus).
Four access paths. The fastest is ZeroTwo: sign in with Google or email, open the chat interface, pick GPT-5 from the model selector, and start prompting. The free trial includes GPT-5 access; ZeroTwo Pro unlocks every variant including gpt-5.4 and gpt-5.5 for $29.99/month — less than ChatGPT Plus at $20/month once you factor in Claude, Gemini, and Grok being bundled.
The second path is chatgpt.com, OpenAI's consumer product. Free users get limited GPT-5 access; Plus at $20/month gives standard quotas; Pro at $200/month unlocks gpt-5 pro with extended reasoning. The third is the OpenAI API at $1.25 input / $10 output per million tokens — pay-as-you-go, no subscription. The fourth is Azure OpenAI for enterprise deployments with data-residency guarantees.
For side-by-side testing, ZeroTwo is the only path that puts GPT-5, Claude Opus 4.6, Gemini 3 Pro, and Grok 4 in the same window — useful both for benchmark cross-checking and for routing each task to the model that handles it best. See also our write-ups on ChatGPT alternatives, the GPT model family, and the full model catalog.
## Key takeaways
- GPT-5 is OpenAI's frontier model, released August 7, 2025, with a 400K-token context window and text/image/audio inputs.
- On AIME 2025 math GPT-5 scores 94.6% without tools, on SWE-bench Verified 74.9%, and on Aider Polyglot 88% — a clear jump over GPT-4o.
- API pricing is $1.25 per million input tokens and $10 per million output tokens; gpt-5 nano is as low as $0.05 / $0.40.
- The GPT-5 family has grown to seven tiers through April 2026 — gpt-5, mini, nano, pro, 5.2, 5.4, and 5.5.
- Independent experts including Simon Willison and Ethan Mollick confirm GPT-5 is a measurable capability jump over GPT-4 and o3.
- The fastest way to try GPT-5 without a ChatGPT Plus subscription is ZeroTwo, which bundles GPT-5 alongside Claude, Gemini, and Grok.
Frequently asked about GPT-5.
Ten direct answers, sourced from OpenAI, Artificial Analysis, Simon Willison, and Ethan Mollick.
> What is GPT-5?
GPT-5 is OpenAI's frontier large language model, launched on August 7, 2025. It succeeds GPT-4o and the o-series reasoning models as the default ChatGPT model, unifying fast responses and extended 'thinking' in a single system. GPT-5 handles text, images, and audio, ships a 400,000-token context window with 128,000 output tokens, and has since expanded into a seven-member family including gpt-5 mini, gpt-5 nano, gpt-5 pro, and the newer gpt-5.2, gpt-5.4, and gpt-5.5 releases through April 2026.
> When was GPT-5 released?
OpenAI released GPT-5 on August 7, 2025, as announced in their official blog post 'Introducing GPT-5'. The release rolled out simultaneously to ChatGPT Free, Plus, Pro, Team, and Enterprise, plus the OpenAI API. GPT-5.2 followed in January 2026, GPT-5.4 in March 2026, and GPT-5.5 on April 23, 2026.
> How does GPT-5 compare to GPT-4o and o3?
GPT-5 improves sharply on every measurable axis. On AIME 2025 math, GPT-5 scores 94.6% without tools versus roughly 74% for GPT-4o; on SWE-bench Verified, 74.9% versus 33.2%; on Aider Polyglot code editing, 88% versus 72%. According to OpenAI, GPT-5's thinking mode produces 80% fewer factual errors than GPT-4o. Against o3, GPT-5 is competitive on reasoning while being roughly 2x cheaper per output token and unifying the 'fast model' and 'thinking model' that previously required manual switching.
> What is the GPT-5 context window?
The original GPT-5 ships a 400,000-token context window with a 128,000-token maximum output, per OpenAI's official API documentation. GPT-5.4, released in March 2026, extended that to a 1.05-million-token context, and GPT-5.5 offers a 1-million context at double the standard price. For reference, 400K tokens is roughly 300,000 words — enough for a full book or a mid-size codebase in one prompt.
> How much does the GPT-5 API cost?
Standard GPT-5 is $1.25 per million input tokens and $10 per million output tokens via OpenAI's Responses and Chat Completions APIs. The cheaper tiers are gpt-5 mini at $0.25 in / $2 out and gpt-5 nano at $0.05 in / $0.40 out. The higher tiers are gpt-5 pro at $15 in / $120 out and gpt-5.5 at $5 in / $30 out. Batch and flex endpoints are 50% cheaper; regional processing adds a 10% uplift for gpt-5.4 variants.
> Can I use GPT-5 without a ChatGPT subscription?
Yes. ChatGPT's Free tier gives every user limited GPT-5 access directly on chatgpt.com. For unlimited access without paying $20/month for ChatGPT Plus, ZeroTwo bundles GPT-5 alongside Claude Opus 4.6, Gemini 3 Pro, and Grok 4 in one multi-model workspace — sign in and pick GPT-5 from the model selector. The OpenAI API is also available pay-as-you-go with no subscription required.
> Is GPT-5 good for coding?
Yes — GPT-5 is one of the three strongest coding models available. It scores 74.9% on SWE-bench Verified (real GitHub issues) and 88% on Aider Polyglot (multi-language code editing), per OpenAI's benchmark report. Independent review from Simon Willison, who had early access at OpenAI's launch event, described GPT-5 as 'fast, effective and highly capable' at code generation. Claude Opus 4.6 edges GPT-5 on expert-task coding, but GPT-5 leads on computer-use and tool-calling benchmarks.
> What do experts say about GPT-5?
Ethan Mollick at Wharton called GPT-5.5 'a sign of the future' and noted rapid AI improvement is continuing, citing GPT-5.5 Pro's coding performance. Simon Willison tested GPT-5 at OpenAI's preview event using his pelican-on-a-bicycle SVG benchmark and concluded it was a meaningful capability jump. Leon Furze at leonfurze.com described the upgrade over GPT-4 as 'a PhD in your pocket' on technical reasoning tasks while cautioning that real-world reliability still lags the benchmarks.
> What does GPT-5.5 add over GPT-5?
GPT-5.5 (April 23, 2026) pushes SWE-bench Verified to 88.7%, MMLU to 92.4%, and adds a claimed 60% reduction in hallucination rate versus GPT-5.4, per OpenAI's introduction post. Three variants ship — standard, Thinking (extended reasoning), and Pro (highest accuracy). Pricing doubles to $5 input / $30 output per million tokens, which VentureBeat's Carl Franzen called 'the first serious frontier-model price hike since the GPT-4 era'.
> How do I try GPT-5 on ZeroTwo?
Sign in to ZeroTwo, open the chat interface, and pick GPT-5 from the model selector — no ChatGPT Plus subscription required. The ZeroTwo free tier includes GPT-5; Pro ($29.99/month) unlocks every variant including gpt-5 pro, gpt-5.4, and gpt-5.5 alongside Claude, Gemini, Grok, and 60+ other frontier models. You can also run GPT-5 side-by-side with Claude Opus 4.6 on the same prompt to compare answers.
The ZeroTwo editorial team tracks every frontier model release, runs benchmark comparisons across our 60+ model catalog, and updates these pages with primary-source numbers — never marketing copy.
published · updated
- > The full GPT model family
- > GPT-5.6 release tracker — diff vs GPT-5.5
- > GPT-6 release date and rumor tracker
- > ChatGPT alternatives, compared
- > Grok — xAI's frontier model
- > Grok 4 — GPT-5's main rival, benchmarked
- > Perplexity AI — search-native chat
- > AI chat — GPT-5, Claude, Gemini side-by-side
- > Every AI model in one catalog
Use GPT-5 without the lock-in_
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