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Claude Sonnet 5.5 vs Claude Opus 5.5

Detailed technical comparison between Claude Sonnet 5.5 (Anthropic) and Claude Opus 5.5 (Anthropic). Review live API token pricing, context window capabilities, time-to-first-token latency, and verified benchmark scores side-by-side.

⚡ Executive Summary & Verdict

Comparison Snapshot

Claude Sonnet 5.5: 3 WinsvsClaude Opus 5.5: 3 Wins
Context Leader

Tie

Equal Capacity
Agentic Tool-Calling

Tie

Equal Capability
Lowest Latency (TTFT)

Tie

Equal Speed
Input Price Leader

Claude Sonnet 5.5

$2.00 / MTok
Anthropicactive

Claude Sonnet 5.5

Claude Sonnet 5.5 is an advanced artificial intelligence model engineered by Anthropic. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Claude Sonnet 5.5 represents a key architectural iteration in the Anthropic model family. First released in 2026-09-28, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,000,000 tokens (approximately 1,333 words), Claude Sonnet 5.5 processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View Claude Sonnet 5.5 Full Specs →
Anthropicactive

Claude Opus 5.5

Claude Opus 5.5 is an advanced artificial intelligence model engineered by Anthropic. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Claude Opus 5.5 represents a key architectural iteration in the Anthropic model family. First released in 2026-09-22, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,000,000 tokens (approximately 1,333 words), Claude Opus 5.5 processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View Claude Opus 5.5 Full Specs →

Technical Specifications

🏆 = Superior Spec
SpecificationClaude Sonnet 5.5Claude Opus 5.5
ProviderAnthropicAnthropic
Context Window1,000,000 tokens1,000,000 tokens
Agent SuitabilityNot yet benchmarkedNot yet benchmarked
Time to First Token (TTFT)No public TTFT dataNo public TTFT data
Deployment Modelmanaged apimanaged api
Production StabilityBeta Access (est.)Beta Access (est.)
API AvailableYesYes
Released Date2026-09-282026-09-22

API Pricing Comparison

Input Price per Million Tokens

Claude Sonnet 5.5

$2.00

Claude Opus 5.5

$4.00

Output Price per Million Tokens

Claude Sonnet 5.5

$10.00

Claude Opus 5.5

$20.00

💡 Cost Ratio: Claude Sonnet 5.5 is 2.0x cheaper per input token than Claude Opus 5.5.

Want to test both models live?

Run side-by-side prompt benchmarks in our dynamic multi-model Sandbox. Compare execution speeds, latency metrics, and compute actual costs in real-time.

Benchmark Performance Metrics

Standardized Scores (0–100%)

Scores show verified raw accuracy percentages across standardized AI evaluation suites. Higher bars indicate superior performance in that domain.

MMLUGeneral knowledge & multi-task understanding
81.2%vs80.4%+0.8% Claude Sonnet 5.5
Claude Sonnet 5.5 🏆
Claude Opus 5.5
HumanEvalPython coding & logic synthesis
79.4%vs78.6%+0.8% Claude Sonnet 5.5
Claude Sonnet 5.5 🏆
Claude Opus 5.5
MATHComplex mathematical problem solving
56.6%vs55.8%+0.8% Claude Sonnet 5.5
Claude Sonnet 5.5 🏆
Claude Opus 5.5
GPQAGraduate-level expert reasoning
38.6%vs41.2%+2.6% Claude Opus 5.5
Claude Sonnet 5.5
Claude Opus 5.5 🏆
HellaSwagCommonsense reasoning and inference
80.8%vs83.4%+2.6% Claude Opus 5.5
Claude Sonnet 5.5
Claude Opus 5.5 🏆
MT-BenchMulti-turn conversation flow quality
8.3%vs8.6%+0.3% Claude Opus 5.5
Claude Sonnet 5.5
Claude Opus 5.5 🏆

Claude Sonnet 5.5 Quirks & Gotchas

No developer gotchas reported.

Claude Opus 5.5 Quirks & Gotchas

No developer gotchas reported.

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