Claude Sonnet 4.6 vs GPT-5.5

Claude Sonnet 4.6 (2026) and GPT-5.5 (2026) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Sonnet 4.6 ships a 1m-token context window, while GPT-5.5 ships a 1.05m-token context window. On MMLU PRO, GPT-5.5 leads by 0.8 pts. On pricing, Claude Sonnet 4.6 costs $3/1M input tokens; GPT-5.5 ranges from $5 to $8/1M input tokens by tier. 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 Sonnet 4.6 when coding workflow support matters.

Decision scorecard

Local evidence first
SignalClaude Sonnet 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$15/1M tokens$30/1M tokens
Provider routes6 tracked4 tracked
Shared benchmarks13 sharedMMLU PRO leader

Decision tradeoffs

Choose Claude Sonnet 4.6 when...
  • Claude Sonnet 4.6 holds a shared-benchmark lead on AIME 2025, ahead by 12.8 points.
  • Claude Sonnet 4.6 has the lower cheapest tracked output price at $15/1M tokens.
  • Claude Sonnet 4.6 has broader tracked provider coverage for fallback and route flexibility.
  • Claude Sonnet 4.6 uniquely exposes Computer use and Parallel agents in local model data.
  • Local decision data tags Claude Sonnet 4.6 for Coding, RAG, and Agents.
Choose GPT-5.5 when...
  • GPT-5.5 holds a shared-benchmark lead on MMLU PRO, ahead by 0.8 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 Sonnet 4.6

Claude Sonnet 4.6

$6,150

Cheapest tracked route/tier: OpenRouter

GPT-5.5

$11,500

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

Estimated monthly gap: $5,350. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Sonnet 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 $15/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Check replacement coverage for Computer use and Parallel agents before moving production traffic.
GPT-5.5 -> Claude Sonnet 4.6
  • Provider overlap exists on OpenRouter, AWS Bedrock, and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Sonnet 4.6 is $15/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Claude Sonnet 4.6 adds Computer use and Parallel agents in local capability data.

Specs

Specification
Released2026-02-172026-04-23
Context window1m1.05m
Parameters——
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-082025-12

Pricing and availability

Pricing attributeClaude Sonnet 4.6GPT-5.5
Input price$3/1M 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$15/1M 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
OpenRouterAnthropicAWS BedrockGCP Vertex AIMicrosoft FoundryVercel AI Gateway
OpenAI APIOpenRouterVercel AI GatewayAWS Bedrock

Capabilities

CapabilityClaude Sonnet 4.6GPT-5.5
VisionYesYes
MultimodalYesYes
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useYesNo
Parallel agentsYesNo

Benchmarks

BenchmarkClaude Sonnet 4.6GPT-5.5
MMLU PRO87.388.1
SWE-bench Verified79.682.6
Google-Proof Q&A89.993.6
AIME 202594.081.2
Humanity's Last Exam33.241.4
HumanEval98.094.2
Chatbot Arena1459.01488.0
ARC-AGI-258.385.0
Terminal-Bench 2.059.182.7
MCP-Atlas61.375.3
MMMU Pro75.688.3
Massive Multitask Language Understanding89.392.4
CursorBench49.046.6

Continue comparing

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