LLM Reference

Claude Opus 4.6 vs GPT-5.5 Pro

Claude Opus 4.6 (2026) and GPT-5.5 Pro (2026) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Opus 4.6 ships a 1m-token context window, while GPT-5.5 Pro ships a 1.05m-token context window. On SWE-bench Verified, GPT-5.5 Pro leads by 1.8 pts. On pricing, Claude Opus 4.6 costs $5/1M input tokens versus $30/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Claude Opus 4.6 is ~500% cheaper at $5/1M; pay for GPT-5.5 Pro only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude Opus 4.6GPT-5.5 Pro
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$180/1M tokens
Provider routes6 tracked3 tracked
Shared benchmarks6 sharedSWE-bench Verified leader

Decision tradeoffs

Choose Claude Opus 4.6 when...
  • 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 Pro when...
  • GPT-5.5 Pro holds a shared-benchmark lead on SWE-bench Verified, ahead by 1.8 points.
  • GPT-5.5 Pro has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Local decision data tags GPT-5.5 Pro 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 Pro

$69,000

Cheapest tracked route/tier: OpenAI API <=272K tokens (standard)

Estimated monthly gap: $58,750. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Opus 4.6 -> GPT-5.5 Pro
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • GPT-5.5 Pro is $155/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
GPT-5.5 Pro -> Claude Opus 4.6
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Opus 4.6 is $155/1M 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 Pro
Input price$5/1M tokens$30/1M tokens
Output price$25/1M tokens$180/1M tokens
Providers
AnthropicAWS BedrockGCP Vertex AIMicrosoft FoundryOpenRouterVercel AI Gateway
OpenAI APIOpenRouterVercel AI Gateway

Capabilities

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

Benchmarks

BenchmarkClaude Opus 4.6GPT-5.5 Pro
SWE-bench Verified80.882.6
SWE-bench Pro53.458.6
Google-Proof Q&A91.393.6
LiveCodeBench70.291.0
Terminal-Bench 2.065.482.7
MCP-Atlas62.775.3

Continue comparing

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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.