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Claude Opus 4.8 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 4.8 and Claude Sonnet 4.5.

Anthropic

Claude Opus 4.8

Claude Opus 4.8 is Anthropic's most capable generally available model in the Opus family. It supports text, image, and file inputs with text output, with reasoning support and a 1M-token...

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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 4.8Claude Sonnet 4.5
ProviderAnthropicAnthropic
Context Window1,000,000 tokens1,000,000 tokens
Agent Suitability97/10091/100
Time to First Token (TTFT)520 ms380 ms
Deployment Modelmanaged apimanaged api
Production Stabilitybetastable
API AvailableYesYes
Released Date2026-05-272025-09-29

API Pricing Comparison

Input Price per Million Tokens

Claude Opus 4.8

$5.00

Claude Sonnet 4.5

$3.00

Output Price per Million Tokens

Claude Opus 4.8

$25.00

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
9540.0%vs8950.0%
Claude Opus 4.8
Claude Sonnet 4.5
HumanEvalPython coding & logic synthesis
9720.0%vs9280.0%
Claude Opus 4.8
Claude Sonnet 4.5
MATHComplex mathematical problem solving
9410.0%vs8000.0%
Claude Opus 4.8
Claude Sonnet 4.5
GPQAGraduate-level expert reasoning
8650.0%vs6250.0%
Claude Opus 4.8
Claude Sonnet 4.5
HellaSwagCommonsense reasoning and inference
9920.0%vs9580.0%
Claude Opus 4.8
Claude Sonnet 4.5
MT-BenchMulti-turn conversation flow quality
980.0%vs930.0%
Claude Opus 4.8
Claude Sonnet 4.5

Claude Opus 4.8 Quirks & Gotchas

  • Best-in-class for autonomous code repair and multi-agent orchestration
  • Preview model — API may introduce breaking changes without notice

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