LLM Reference

Claude 3.7 Sonnet vs GPT-5.5 Instant

Claude 3.7 Sonnet (2024) and GPT-5.5 Instant (2026) are frontier reasoning models from Anthropic and OpenAI. Claude 3.7 Sonnet ships a 200k-token context window, while GPT-5.5 Instant ships a 400k-token context window. On pricing, Claude 3.7 Sonnet costs $3/1M input tokens versus $5/1M 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 3.7 Sonnet is ~67% cheaper at $3/1M; pay for GPT-5.5 Instant only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude 3.7 SonnetGPT-5.5 Instant
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsmultimodal apps and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window200k400k
Cheapest output$15/1M tokens$30/1M tokens
Provider routes6 tracked1 tracked
Shared benchmarks0 shared0 shared

Decision tradeoffs

Choose Claude 3.7 Sonnet when...
  • Claude 3.7 Sonnet has the lower cheapest tracked output price at $15/1M tokens.
  • Claude 3.7 Sonnet has broader tracked provider coverage for fallback and route flexibility.
  • Claude 3.7 Sonnet uniquely exposes Reasoning in local model data.
  • Local decision data tags Claude 3.7 Sonnet for Coding, RAG, and Agents.
Choose GPT-5.5 Instant when...
  • GPT-5.5 Instant has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Local decision data tags GPT-5.5 Instant 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 3.7 Sonnet

Claude 3.7 Sonnet

$6,150

Cheapest tracked route/tier: GCP Vertex AI

GPT-5.5 Instant

$11,500

Cheapest tracked route/tier: OpenAI API

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

Switch friction

Claude 3.7 Sonnet -> GPT-5.5 Instant
  • No overlapping tracked provider route is sourced for Claude 3.7 Sonnet and GPT-5.5 Instant; plan for SDK, billing, or endpoint changes.
  • GPT-5.5 Instant is $15/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Check replacement coverage for Reasoning before moving production traffic.
GPT-5.5 Instant -> Claude 3.7 Sonnet
  • No overlapping tracked provider route is sourced for GPT-5.5 Instant and Claude 3.7 Sonnet; plan for SDK, billing, or endpoint changes.
  • Claude 3.7 Sonnet is $15/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Claude 3.7 Sonnet adds Reasoning in local capability data.

Specs

Specification
Released2024-03-042026-05-05
Context window200k400k
Parameters
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2024-112025-08

Pricing and availability

Pricing attributeClaude 3.7 SonnetGPT-5.5 Instant
Input price$3/1M tokens$5/1M tokens
Output price$15/1M tokens$30/1M tokens
Providers

Capabilities

CapabilityClaude 3.7 SonnetGPT-5.5 Instant
VisionYesYes
MultimodalYesYes
ReasoningYesNo
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

No shared benchmark scores are currently available for this pair.

Continue comparing

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