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Claude Opus 4 vs Claude Sonnet 4.5

How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Opus 4 and Claude Sonnet 4.5.

Anthropic

Claude Opus 4

Claude Opus 4 is benchmarked as the world’s best coding model, at time of release, bringing sustained performance on complex, long-running tasks and agent workflows. It sets new benchmarks in...

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Anthropic

Claude Sonnet 4.5

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with...

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Technical Specifications

SpecificationClaude Opus 4Claude Sonnet 4.5
ProviderAnthropicAnthropic
Context Window200,000 tokens1,000,000 tokens
Agent SuitabilityN/A91/100
Time to First Token (TTFT)N/A380 ms
Deployment Modelmanaged apimanaged api
Production Stabilitystablestable
API AvailableYesYes
Released Date2025-05-222025-09-29

API Pricing Comparison

Input Price per Million Tokens

Claude Opus 4

$15.00

Claude Sonnet 4.5

$3.00

Output Price per Million Tokens

Claude Opus 4

$75.00

Claude Sonnet 4.5

$15.00

Want to test both models live?

Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.

Benchmark Performance Metrics

Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.

MMLUGeneral knowledge & multi-task understanding
9050.0%vs8950.0%
Claude Opus 4
Claude Sonnet 4.5
HumanEvalPython coding & logic synthesis
9300.0%vs9280.0%
Claude Opus 4
Claude Sonnet 4.5
MATHComplex mathematical problem solving
8540.0%vs8000.0%
Claude Opus 4
Claude Sonnet 4.5
GPQAGraduate-level expert reasoning
7230.0%vs6250.0%
Claude Opus 4
Claude Sonnet 4.5
HellaSwagCommonsense reasoning and inference
9650.0%vs9580.0%
Claude Opus 4
Claude Sonnet 4.5
MT-BenchMulti-turn conversation flow quality
945.0%vs930.0%
Claude Opus 4
Claude Sonnet 4.5

Claude Opus 4 Quirks & Gotchas

No developer gotchas reported.

Claude Sonnet 4.5 Quirks & Gotchas

  • Excellent for long-form writing and nuanced document analysis
  • Slightly slower than Sonnet 4.6 — upgrade for production agentic use