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Claude Opus 4.8 vs Claude Opus 5.5

Detailed technical comparison between Claude Opus 4.8 (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 Opus 4.8: 6 WinsvsClaude Opus 5.5: 0 Wins
Context Leader

Tie

Equal Capacity
Agentic Tool-Calling

Tie

Equal Capability
Lowest Latency (TTFT)

Tie

Equal Speed
Input Price Leader

Claude Opus 5.5

$4.00 / MTok
Anthropicactive

Claude Opus 4.8

Claude Opus 4.8 is an advanced artificial intelligence model engineered by Anthropic. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Claude Opus 4.8 represents a key architectural iteration in the Anthropic model family. First released in 2026-05-27, 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 4.8 processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View Claude Opus 4.8 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 Opus 4.8Claude Opus 5.5
ProviderAnthropicAnthropic
Context Window1,000,000 tokens1,000,000 tokens
Agent Suitability97/100 (est.)Not yet benchmarked
Time to First Token (TTFT)520 ms (est.)No public TTFT data
Deployment Modelmanaged apimanaged api
Production StabilityBeta Access (est.)Beta Access (est.)
API AvailableYesYes
Released Date2026-05-272026-09-22

API Pricing Comparison

Input Price per Million Tokens

Claude Opus 4.8

$5.00

Claude Opus 5.5

$4.00

Output Price per Million Tokens

Claude Opus 4.8

$25.00

Claude Opus 5.5

$20.00

💡 Cost Ratio: Claude Opus 5.5 is 1.3x cheaper per input token than Claude Opus 4.8.

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
95.4%vs80.4%+15.0% Claude Opus 4.8
Claude Opus 4.8 🏆
Claude Opus 5.5
HumanEvalPython coding & logic synthesis
97.2%vs78.6%+18.6% Claude Opus 4.8
Claude Opus 4.8 🏆
Claude Opus 5.5
MATHComplex mathematical problem solving
94.1%vs55.8%+38.3% Claude Opus 4.8
Claude Opus 4.8 🏆
Claude Opus 5.5
GPQAGraduate-level expert reasoning
86.5%vs41.2%+45.3% Claude Opus 4.8
Claude Opus 4.8 🏆
Claude Opus 5.5
HellaSwagCommonsense reasoning and inference
99.2%vs83.4%+15.8% Claude Opus 4.8
Claude Opus 4.8 🏆
Claude Opus 5.5
MT-BenchMulti-turn conversation flow quality
9.8%vs8.6%+1.2% Claude Opus 4.8
Claude Opus 4.8 🏆
Claude Opus 5.5

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 Opus 5.5 Quirks & Gotchas

No developer gotchas reported.

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