The arena · AI model review
GPT-5.5
by OpenAI
OpenAI's agentic flagship: 1M context, SOTA ARC-AGI-2 and Terminal-Bench 2.0, $5/$30 per 1M tokens.
$30/1M out
Standard tier $5/$30 per 1M tokens (cached input $0.50), double GPT-5.4's $2.50/$15; Batch/Flex $2.50/$15; Priority $12.50/$75; GPT-5.5 Pro $30/$180; prompts over 272K input tokens billed 2x in / 1.5x out.
OpenAI
1M tokens (1,050,000)
$5/1M in
$30/1M out
text, vision (image input, text output)
No
What is GPT-5.5?
OpenAI's flagship reasoning model, released April 23, 2026. Built for agentic coding, computer use, and long-horizon knowledge work, with a 1,050,000-token context window and 128K max output. Accepts text and image input, outputs text, with function calling, structured outputs, and hosted agent tools via the Responses API.
GPT-5.5 pros & cons
Pros
- 1M-token context window (1,050,000) with 128K max output and reasoning effort tunable from none to xhigh
- State-of-the-art ARC-AGI-2 at 85.0% (vs 73.3% for GPT-5.4) and Terminal-Bench 2.0 at 82.7%
- Strong agentic coding autonomy: devs report it one-shots tasks that took GPT-5.4 multiple turns and fixes its own mistakes; +50 points on Code Arena vs GPT-5.4
- Aggressive discounts: 90% off cached input ($0.50/1M) and 50% off via Batch or Flex ($2.50/$15)
- Fast for a frontier reasoner: devs say it is the first GPT model comfortable to run at medium or low thinking effort
Cons
- List price doubled vs GPT-5.4 ($5/$30 vs $2.50/$15) for the same 1M-token context window
- Overly literal instruction-following: devs report it fails to infer intent in obvious places where Claude succeeds
- Trails Claude Opus 4.8 on SWE-bench Pro (58.6% vs 69.2%); HN developers still favor Claude roughly 2:1 for coding
- Sometimes too conservative with code changes or skips deep reasoning entirely, answering immediately on complex prompts
- Long-context surcharge: prompts over 272K input tokens are billed 2x input and 1.5x output for the whole session
The arena’s verdict
Pick GPT-5.5 over GPT-5.4 if you need stronger agentic autonomy, terminal-heavy workflows, or SOTA abstract reasoning, but know the list price doubled from GPT-5.4's $2.50/$15 to $5/$30 while the 1M-token context stayed the same. Teams doing high-stakes multi-file refactoring may still prefer Claude Opus, which leads SWE-bench Pro (69.2% vs 58.6%) and infers intent better from loose prompts. Budget-sensitive users should mind the 272K-token surcharge and reports of faster limit burn, and lean on caching, Batch, or Flex to halve costs.
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Top GPT-5.5 alternatives
All alternativesAnthropic's fastest model: about 90% of Sonnet 4.5's coding skill at $1/$5 per 1M tokens, 200K context.
Anthropic's April 2026 Opus: 87.6% SWE-bench Verified, 1M context, high-res vision, now behind Opus 4.8
Anthropic's flagship Opus-tier model for long-horizon agentic coding; 1M context at $5/$25 per 1M tokens.
Compare GPT-5.5 head-to-head
What the crowd says
“It is painfully literal. Where Claude infers intent in obvious places, 5.5 wants everything spelled out. And the price doubled vs 5.4 for the same 1M context.”
“85 on ARC-AGI-2 and you can feel it. Stuff that used to stall my agent just resolves now. 1M context with 128K output covers every workflow I have.”
“5.5 one-shots tasks that took 5.4 three turns, and it fixes its own mistakes mid-run instead of doubling down. The reasoning effort dial from none to xhigh is genuinely useful.”
GPT-5.5: frequently asked questions
How much does GPT-5.5 cost per 1M tokens?
GPT-5.5 costs $5/1M in per 1M input tokens and $30/1M out per 1M output tokens. Standard tier $5/$30 per 1M tokens (cached input $0.50), double GPT-5.4's $2.50/$15; Batch/Flex $2.50/$15; Priority $12.50/$75; GPT-5.5 Pro $30/$180; prompts over 272K input tokens billed 2x in / 1.5x out.