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Claude 3.5 SonnetvsClaude Opus 4

Anthropic vs Anthropic — Side-by-side model comparison

Claude 3.5 Sonnet leads 2/5 categories

Head-to-Head Comparison

MetricClaude 3.5 SonnetClaude Opus 4
Provider
Arena Rank
#8
#1
Context Window
200K
200K
Input Pricing
$3.00/1M tokens
$5.00/1M tokens
Output Pricing
$15.00/1M tokens
$25.00/1M tokens
Parameters
Undisclosed
Undisclosed
Open Source
No
No
Best For
Coding, analysis, writing, vision
Complex reasoning, coding, agentic tasks
Release Date
Oct 22, 2024
May 22, 2025

Claude 3.5 Sonnet

Claude 3.5 Sonnet was Anthropic's previous generation balanced model that set new industry benchmarks when released. It demonstrated that mid-tier models could compete with and even surpass flagship models from competitors on coding, reasoning, and analysis tasks. The model featured a 200K token context window and introduced Anthropic's Artifacts feature for interactive code execution. Claude 3.5 Sonnet became one of the most popular models for professional developers and enterprises, known for its excellent code generation, careful instruction following, and reduced hallucination rates. While now succeeded by Claude Sonnet 4, it remains widely deployed in production systems and continues to offer strong performance at its price point. It was instrumental in establishing Anthropic as a serious competitor to OpenAI.

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Claude Opus 4

Claude Opus 4 is Anthropic's most powerful AI model, holding the #1 position on the Chatbot Arena leaderboard. It represents a breakthrough in extended thinking and agentic capabilities, able to work autonomously on complex multi-step tasks for hours. With a 200K token context window, it excels at analyzing entire codebases, lengthy legal documents, and research papers in a single pass. The model demonstrates exceptional performance in coding (setting new benchmarks on SWE-bench), advanced reasoning, and nuanced writing tasks. Its agentic capabilities allow it to use tools, navigate computers, and execute multi-step workflows with minimal human oversight. Opus 4 is the preferred choice for enterprises requiring the highest quality output on mission-critical tasks where accuracy and depth matter more than speed or cost.

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Key Differences: Claude 3.5 Sonnet vs Claude Opus 4

1

Claude Opus 4 ranks higher in arena benchmarks (#1) indicating stronger overall performance.

2

Claude 3.5 Sonnet is 1.7x cheaper on average, making it the better choice for high-volume applications.

C

When to use Claude 3.5 Sonnet

  • +Budget is a concern and you need cost efficiency
  • +Your use case involves coding, analysis, writing, vision
View full Claude 3.5 Sonnet specs →
C

When to use Claude Opus 4

  • +You need the highest quality output based on arena rankings
  • +Quality matters more than cost
  • +Your use case involves complex reasoning, coding, agentic tasks
View full Claude Opus 4 specs →

Cost Analysis

At current pricing, Claude 3.5 Sonnet is 1.7x more affordable than Claude Opus 4. For a typical enterprise workload processing 100M tokens per month:

Claude 3.5 Sonnet monthly cost

$900

100M tokens/mo (50/50 in/out)

Claude Opus 4 monthly cost

$1,500

100M tokens/mo (50/50 in/out)

The Verdict

Claude 3.5 Sonnet wins our head-to-head comparison with 2 out of 5 category wins. It's the stronger choice for coding, analysis, writing, vision, though Claude Opus 4 holds an edge in complex reasoning, coding, agentic tasks.

Last compared: April 2026 · Data sourced from public benchmarks and official pricing pages

Frequently Asked Questions

Which is better, Claude 3.5 Sonnet or Claude Opus 4?
In our head-to-head comparison, Claude 3.5 Sonnet leads in 2 out of 5 categories (arena rank, context window, input pricing, output pricing, and parameters). Claude 3.5 Sonnet excels at coding, analysis, writing, vision, while Claude Opus 4 is better suited for complex reasoning, coding, agentic tasks. The best choice depends on your specific requirements, budget, and use case.
How does Claude 3.5 Sonnet pricing compare to Claude Opus 4?
Claude 3.5 Sonnet charges $3.00 per 1M input tokens and $15.00 per 1M output tokens. Claude Opus 4 charges $5.00 per 1M input tokens and $25.00 per 1M output tokens. Claude 3.5 Sonnet is the more affordable option, approximately 1.7x cheaper on average. For high-volume production workloads, the pricing difference can significantly impact total cost of ownership.
What is the context window difference between Claude 3.5 Sonnet and Claude Opus 4?
Claude 3.5 Sonnet supports a 200K token context window, while Claude Opus 4 supports 200K tokens. Context window size matters most for tasks involving long documents, large codebases, or extended conversations.
Can I use Claude 3.5 Sonnet or Claude Opus 4 for free?
Claude 3.5 Sonnet is a paid API model starting at $3.00 per 1M input tokens. Claude Opus 4 is a paid API model starting at $5.00 per 1M input tokens.
Which model has better benchmarks, Claude 3.5 Sonnet or Claude Opus 4?
Claude 3.5 Sonnet holds arena rank #8, while Claude Opus 4 holds rank #1. Claude Opus 4 performs better in overall arena benchmarks, which aggregate human preference ratings across coding, reasoning, and general tasks. Note that benchmarks don't capture every use case — we recommend testing both models on your specific tasks.
Is Claude 3.5 Sonnet or Claude Opus 4 better for coding?
Claude 3.5 Sonnet is specifically optimized for coding tasks. Claude Opus 4 is specifically optimized for coding tasks. For coding specifically, arena rank and code-specific benchmarks are the best indicators of performance.