Claude Opus 4.6 vs GPT-5.5

Claude Opus 4.6 (2026) and GPT-5.5 (2026) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Opus 4.6 ships a 1m-token context window, while GPT-5.5 ships a 1.05m-token context window. On MMLU PRO, Claude Opus 4.6 leads by 1 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

GPT-5.5 is safer overall; choose Claude Opus 4.6 when coding workflow support matters.

Decision scorecard

Local evidence first
SignalClaude Opus 4.6GPT-5.5
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsreasoning-heavy apps, multimodal apps, and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m1.05m
Cheapest output$25/1M tokens$30/1M tokens
Provider routes6 tracked4 tracked
Shared benchmarksMMLU PRO leader15 shared

Decision tradeoffs

Choose Claude Opus 4.6 when...
  • Claude Opus 4.6 holds a shared-benchmark lead on MMLU PRO, ahead by 1 points.
  • Claude Opus 4.6 has the lower cheapest tracked output price at $25/1M tokens.
  • Claude Opus 4.6 has broader tracked provider coverage for fallback and route flexibility.
  • Local decision data tags Claude Opus 4.6 for Coding, RAG, and Agents.
Choose GPT-5.5 when...
  • GPT-5.5 holds a shared-benchmark lead on SWE-bench Verified, ahead by 1.8 points.
  • GPT-5.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Local decision data tags GPT-5.5 for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate Claude Opus 4.6

Claude Opus 4.6

$10,250

Cheapest tracked route/tier: Anthropic

GPT-5.5

$11,500

Cheapest tracked route/tier: OpenAI API 0-272K input tokens

Estimated monthly gap: $1,250. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Opus 4.6 -> GPT-5.5
  • Provider overlap exists on OpenRouter, Vercel AI Gateway, and AWS Bedrock; start route-level A/B tests there.
  • GPT-5.5 is $5/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
GPT-5.5 -> Claude Opus 4.6
  • Provider overlap exists on AWS Bedrock, OpenRouter, and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Opus 4.6 is $5/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.

Specs

Specification
Released2026-02-052026-04-23
Context window1m1.05m
Parameters——
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-122025-12

Pricing and availability

Pricing attributeClaude Opus 4.6GPT-5.5
Input price$5/1M tokens
0-272K input tokens
$5/1M tokens
Standard GPT-5.5 token pricing before the long-context surcharge threshold.
272K+ input tokens
$8/1M tokens
Long-context surcharge applies above 272K input tokens for the full session.
Output price$25/1M tokens
0-272K input tokens
$30/1M tokens
Standard GPT-5.5 token pricing before the long-context surcharge threshold.
272K+ input tokens
$36/1M tokens
Long-context surcharge applies above 272K input tokens for the full session.
Providers
AnthropicAWS BedrockGCP Vertex AIMicrosoft FoundryOpenRouterVercel AI Gateway
OpenAI APIOpenRouterVercel AI GatewayAWS Bedrock

Capabilities

CapabilityClaude Opus 4.6GPT-5.5
VisionYesYes
MultimodalYesYes
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Opus 4.6GPT-5.5
MMLU PRO89.188.1
SWE-bench Verified80.882.6
SWE-bench Pro53.458.6
Google-Proof Q&A91.393.6
AIME 202594.281.2
Humanity's Last Exam53.041.4
HumanEval95.094.2
Terminal-Bench 2.065.482.7
ARC-AGI-268.885.0
Aider Polyglot72.088.0
Chatbot Arena1501.01488.0
MCP-Atlas62.775.3
MMMU Pro77.388.3
Massive Multitask Language Understanding91.192.4
BrowseComp84.084.4

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Last reviewed: 2026-10-07. Data sourced from public model cards and provider documentation.