Claude Sonnet 5 vs GPT-5.5

API pricing, context window and capabilities for Claude Sonnet 5 and GPT-5.5, side by side. Prices are the cheapest listed serving route per 1M tokens, from LiteLLM and OpenRouter.

Verdict

computed from the published numbers

Claude Sonnet 5 wins on price. GPT-5.5 wins on Terminal-Bench, on intelligence and on context window.

Price
Claude Sonnet 5
Terminal-Bench
GPT-5.5
Intelligence
GPT-5.5
Context window
GPT-5.5

Key takeaways

who wins on what, from the published numbers

Claude Sonnet 5 wins

  • Cheaper input ($2.00 vs $5.00 /1M)
  • Cheaper output ($10.00 vs $30.00 /1M)
  • More serving providers (9 vs 6)

GPT-5.5 wins

  • Larger context window (1M vs 1.1M)
Cheaper overall
Claude Sonnet 5
$2.00 + $10.00 /1M
Larger context
GPT-5.5
1.1M
More providers
Claude Sonnet 5
9 providers

Pricing & specs

cheapest listed route · per 1M tokens
On-demand listed rates, OpenRouter routed quotes and Vercel reseller quotes. Enterprise commitments can be materially lower.
Claude Sonnet 5GPT-5.5
Input $/1M$2.00via Anthropic best$5.00via OpenAI
Output $/1M$10.00via Anthropic best$30.00via OpenAI
Context window1M 1.1M best
Max output128K 128K
Serving providers9 best6
DateReleased Jun 30, 2026 Released Apr 23, 2026

Benchmarks

Benchmark scores, side by side
Claude Sonnet 5GPT-5.5
Intelligence38.2 38.4 best
Terminal-Bench81% 84% best
GPQA Diamond91% 94% best
Output speed85 t/s 102 t/s best
Latency (TTFT)187.72s 70.60s best

Cost calculator

choose a serving route for each side
Input tokens / month
Output tokens / month
Claude Sonnet 5
via Azure
$20
GPT-5.5
via OpenAI
$55

Capabilities

feature support, side by side
FeatureClaude Sonnet 5GPT-5.5
Vision✓✓
Tool use✓✓
Reasoning✓✓
Audio——
Prompt caching✓✓
Structured output✓✓
Web search✓✓

Related comparisons

Frequently asked questions

Which is cheaper, Claude Sonnet 5 or GPT-5.5?
Claude Sonnet 5 is cheaper for input ($2.00 vs $5.00 per 1M tokens) from Anthropic. Claude Sonnet 5 is cheaper for output ($10.00 vs $30.00 per 1M tokens) from Anthropic.
What is the context window difference between Claude Sonnet 5 and GPT-5.5?
Claude Sonnet 5 has a 1M-token context window and GPT-5.5 has 1.1M tokens, so GPT-5.5 can take a larger prompt.
How do Claude Sonnet 5 and GPT-5.5 compare on benchmarks?
On the tracked benchmarks, GPT-5.5 leads on Terminal-Bench, and GPT-5.5 leads on intelligence.
Listed prices from LiteLLM, OpenRouter and Vercel · last checked Oct 14, 2026

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