ChatGPT-5.5ChatGPT GPT-5.5 — Flagship model and GPT-5.5 Instant review
In-depth review of ChatGPT powered by GPT-5.5. We evaluate OpenAI's flagship models, API pricing, context length capabilities, and how it holds up against Anthropic's Claude Fable 5.
Four metrics, one decision.
ChatGPT GPT-5.5 re-establishes OpenAI at the absolute frontier of conversational AI, offering unparalleled response speed with GPT-5.5 Instant and deep reasoning with GPT-5.5. Here's what we found.
The new standard of versatile consumer AI.OpenAI's GPT-5.5 and GPT-5.5 Instant deliver a superb combination of logical capacity and speed. With a 512K context window, competitive API pricing ($4/$12 per 1M tokens), and native multimedia integration, it remains a must-have tool for creators, developers, and businesses alike.
- Best forGeneral-purpose reasoning, fast coding loops, and multimodal creation
- Learning curveLow
- Top alternativeClaude Fable 5
ChatGPT-5.5 represents OpenAI's next-generation flagship AI lineup released in spring 2026. It introduces GPT-5.5 (released April 23, 2026) for heavy reasoning tasks, and GPT-5.5 Instant (released May 5, 2026) for fast, budget-friendly pipelines.
This release features a substantial increase in context capacity to 512K tokens, and slashes API pricing to $4.00 input / $12.00 output per million tokens, representing a highly competitive response to Anthropic's Mythos series.
- Flagship GPT-5.5 with massive logical, math, and code generation improvements
- GPT-5.5 Instant offering high-volume tasks under 50ms latency
- Context window expanded to 512K tokens for the flagship model
- Free tier upgraded to GPT-5.5-mini for all active users
Stress Test: Complex Math Formulation and Logic Chain
We tested GPT-5.5 on a complex math formulation and multi-stage logic puzzle, comparing it to Claude Fable 5.
Flawless logic chain, extremely fast response. Formatted LaTeX correctly.
Slightly more comprehensive explanation, but twice the latency.
Failed one logical constraint in the third puzzle stage.
Methodology note. Each prompt was run three times in separate sessions, with no system prompt, at UTC 09:00. The score is the median of three reviewers blinded to the tool. See full methodology.
Three plans, one clear.
GPT-5.5-mini with generous daily limits
Full GPT-5.5 and GPT-5.5 Instant, DALL-E 3, Custom GPTs
Higher caps, shared workspace, workspace integration
The good and the painful.
- Excellent speed-to-intelligence ratio with GPT-5.5 Instant
- Massive 512K context window for flagship GPT-5.5
- Very competitive API token pricing ($4/$12 per 1M)
- Superb developer and Custom GPT ecosystem
- Trails Claude Fable 5 on complex multi-file software engineering tasks
- Plus consumer caps still apply during peak traffic hours
ChatGPT-5.5 vs the rest.
Where it wins and loses against its three direct competitors in 2026.
- Lower API token costs ($4 input / $12 output vs $10/$50)
- Much faster response times for standard developer loops
- Better multimodal integrations and DALL-E 3 default
- Claude Fable 5 has a larger context window (1M) and higher SWE-bench score (80.3% vs ~76%)
- Stronger complex coding and mathematical reasoning
- More customizable ecosystem via Custom GPTs
- Higher output token rate limit for bulk users
- Gemini 3.5 Flash offers 2M context window and deeper Google Workspace integration
Three profiles that get the most out of it.
Developers & Prototypers
Great for fast coding iterations, code explanation, and writing clean scripts in seconds.
Content Creators & Writers
Leverage the high-speed GPT-5.5 Instant for copy variation, research synthesis, and creative brainstorming.
For a versatile and highly cost-effective flagship AI, ChatGPT GPT-5.5remains the absolute industry benchmark.
The addition of GPT-5.5 and GPT-5.5 Instant makes ChatGPT Plus an incredibly powerful value proposition. For $20/month, you get near-frontier logical reasoning, industry-leading speed, and a massive ecosystem. While developers requiring multi-hour agent autonomy might lean towards Claude Fable 5, ChatGPT GPT-5.5 is the best default choice.
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Frequently asked questions.
Related tools
Claude Fable 5
The new standard of "Mythos-Class" intelligence with deep autonomous reasoning.
- New model utilizing frontier "Mythos-Class" intelligence
- 1 million token input context window
- Record-breaking 80.3% score on SWE-bench Pro
- Extended output capacity of up to 128,000 tokens
Claude Sonnet 4.5
The assistant with the best long-context reasoning on the market.
- 200K-token context, no drift
- Beats GPT-4o on long analytical tasks
- Artifacts: edits code and docs live
- Generous Pro plan usage limits
Gemini 3.5 Flash
Unrivaled 2M context window, sub-100ms latency, and autonomous Workspace agents.
- Sub-100ms first-token latency for real-time voice and automation
- Massive 2 million token input context window
- Gemini Spark personal agent for 24/7 background Workspace tasks
- Native cinematic video generation powered by Gemini Omni