Claude Sonnet 4.6 vs GPT-5.5

Claude Sonnet 4.6 and GPT-5.5 are both current production-tier models. Claude Sonnet 4.6 is meaningfully cheaper at $3 / $15 per 1M. Claude Sonnet 4.6 leads on long-context retrieval. GPT-5.5 leads on reasoning, general knowledge, multilingual.

Specs side by side

Metric
Anthropic
Claude Sonnet 4.6
OpenAI
GPT-5.5
Input price (per 1M)$3$5
Output price (per 1M)$15$30
Context window1M tokens1.1M tokens
Speed tierbalancedbalanced
Open weightsNoNo
EU regionYesYes
Free tierNoNo
Prompt cachingYesYes
Vision inputYesYes
Extended thinkingYesYes

When to choose each

Anthropic

Choose Claude Sonnet 4.6 if…

  • Cost is a priority ($3 / $15 per 1M vs $5 / $30 per 1M)
  • Long-context retrieval is central to your workload
OpenAI

Choose GPT-5.5 if…

  • You need realtime speech-to-speech
  • Reasoning is central to your workload
  • General knowledge is central to your workload

Benchmark delta

Claude Sonnet 4.6 leads on

  • Long-context retrieval

GPT-5.5 leads on

  • Reasoning
  • General knowledge
  • Multilingual
  • Vision

FAQ — Claude Sonnet 4.6 vs GPT-5.5

Claude Sonnet 4.6 vs GPT-5.5 — which is better?

Claude Sonnet 4.6 and GPT-5.5 are both current production-tier models. Claude Sonnet 4.6 is meaningfully cheaper at $3 / $15 per 1M. Claude Sonnet 4.6 leads on long-context retrieval. GPT-5.5 leads on reasoning, general knowledge, multilingual. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.

How does Claude Sonnet 4.6 pricing compare to GPT-5.5?

Claude Sonnet 4.6 costs $3 / $15 per 1M vs GPT-5.5 at $5 / $30 per 1M. Claude Sonnet 4.6 is cheaper on output tokens by roughly 100%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.

Does Claude Sonnet 4.6 or GPT-5.5 have the bigger context window?

GPT-5.5 has a 1.1M-token context window — 1× the 1M context of Claude Sonnet 4.6. Enough for entire codebases, books, or multi-document RAG.

Is there a free tier for Claude Sonnet 4.6 or GPT-5.5?

Claude Sonnet 4.6: no — Free via Claude.ai web chat; API requires paid credits. GPT-5.5: no — Paid-only — no free API tier; available via ChatGPT Plus/Pro.

Which is better for coding — Claude Sonnet 4.6 or GPT-5.5?

GPT-5.5 leads on coding benchmarks (Claude Sonnet 4.6: 94/100, GPT-5.5: 95/100). For production coding agents also weigh tool-use performance — Claude Sonnet 4.6 scores 96, GPT-5.5 scores 94.