The AI arena is free today

Open Superagent

Claude 3.5 Sonnet vs Claude Opus 4.1

Claude Opus 4.1 leads the LLM Stats Score 29.9 to 19.1. Claude 3.5 Sonnet is 5.0x cheaper per token.

Anthropic · Anthropic · Updated for 2026

Which is better?

Claude Opus 4.1 leads the overall LLM Stats Score 29.9 to 19.1, ranking #126 overall.

In the 4 individual benchmarks reported for both models, Claude Opus 4.1 wins 4; this is a narrower head-to-head signal than the composite indexes.

On price, Claude 3.5 Sonnet is roughly 5.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude 3.5 Sonnet

  • cost matters — it's about 5.0x cheaper per token

Choose Claude Opus 4.1

  • overall performance matters — it scores 29.9 and ranks #126 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 4 of 4 exact shared results
  • you want the most recent training data — it shipped Aug 2025

At a glance

The differences that matter most.

Core performance indexes
19.1
#210
29.9
#126
20.1
#192
29.9
#122
11.4
#158
21.6
#88
Cost, coverage & limits
Benchmark wins
0 of 4
4 of 4
Input price
$3.00 / M
$15.00 / M
Output price
$15.00 / M
$75.00 / M
Context window
200,000
200,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

3 shared
Index
Claude 3.5 Sonnet
Claude Opus 4.1
23.2#132
22.6#134
8.2#141
18.3#67
9.9#75
19.2#24
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

19 reported for Claude 3.5 Sonnet · 8 for Claude Opus 4.1

4 shared

Claude 3.5 Sonnet outperforms in 0 benchmarks, while Claude Opus 4.1 is better at 4 benchmarks (GPQA, SWE-Bench Verified, TAU-bench Airline, TAU-bench Retail).

Claude Opus 4.1 significantly outperforms across most benchmarks.

Tue Sep 22 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Claude 3.5 Sonnet costs less

For input processing, Claude 3.5 Sonnet ($3.00/1M tokens) is 5.0x cheaper than Claude Opus 4.1 ($15.00/1M tokens).

For output processing, Claude 3.5 Sonnet ($15.00/1M tokens) is 5.0x cheaper than Claude Opus 4.1 ($75.00/1M tokens).

In conclusion, Claude Opus 4.1 is more expensive than Claude 3.5 Sonnet.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Tue Sep 22 2026 • llm-stats.com
Anthropic
Claude 3.5 Sonnet
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
Anthropic
Claude Opus 4.1
Input tokens$15.00
Output tokens$75.00
Best providerAnthropic
Notice missing or incorrect data?Start an Issue

Context Window

Maximum input and output token capacity

Both models have the same input context window of 200,000 tokens. Claude 3.5 Sonnet can generate longer responses up to 200,000 tokens, while Claude Opus 4.1 is limited to 32,000 tokens.

Anthropic
Claude 3.5 Sonnet
Input200,000 tokens
Output200,000 tokens
Anthropic
Claude Opus 4.1
Input200,000 tokens
Output32,000 tokens
Tue Sep 22 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude 3.5 Sonnet and Claude Opus 4.1 support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude 3.5 Sonnet

Text
Images
Audio
Video

Claude Opus 4.1

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude 3.5 Sonnet

Proprietary

Closed source

Claude Opus 4.1

Proprietary

Closed source

Release Timeline

When each model was launched

Claude 3.5 Sonnet was released on 2024-10-22, while Claude Opus 4.1 was released on 2025-08-05.

Claude Opus 4.1 is 10 months newer than Claude 3.5 Sonnet.

Claude 3.5 Sonnet

Oct 22, 2024

1.9 years ago

Claude Opus 4.1

Aug 5, 2025

1.1 years ago

9mo newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

Claude 3.5 Sonnet is available from Anthropic, Bedrock, Google. Claude Opus 4.1 is available from Anthropic, Bedrock, Google.

Claude 3.5 Sonnet

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
bedrock logo
AWS Bedrock
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
google logo
Google
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

Claude Opus 4.1

anthropic logo
Anthropic
Input Price:Input: $15.00/1MOutput Price:Output: $75.00/1M
bedrock logo
AWS Bedrock
Input Price:Input: $15.00/1MOutput Price:Output: $75.00/1M
google logo
Google
Input Price:Input: $15.00/1MOutput Price:Output: $75.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion

Judge for yourself.

Run your own prompts against Claude 3.5 Sonnet and Claude Opus 4.1 side-by-side, then vote on the output you prefer.

Claude 3.5 Sonnet
✓ Preferred
Claude Opus 4.1
Open in Playground

FAQ

Common questions about Claude 3.5 Sonnet vs Claude Opus 4.1.

Which is better, Claude 3.5 Sonnet or Claude Opus 4.1?

Claude Opus 4.1 leads the LLM Stats Score 29.9 to 19.1. Claude 3.5 Sonnet is made by Anthropic and Claude Opus 4.1 is made by Anthropic. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude 3.5 Sonnet compare to Claude Opus 4.1 in benchmarks?

Claude 3.5 Sonnet scores GSM8k: 96.4%, DocVQA: 95.2%, AI2D: 94.7%, HumanEval: 93.7%, BIG-Bench Hard: 93.1%. Claude Opus 4.1 scores MMMLU: 89.5%, TAU-bench Retail: 82.4%, GPQA: 80.9%, AIME 2025: 78.0%, MMMU (validation): 77.1%.

Is Claude 3.5 Sonnet cheaper than Claude Opus 4.1?

Claude 3.5 Sonnet is 5.0x cheaper for input tokens. Claude 3.5 Sonnet costs $3.00/M input and $15.00/M output via anthropic. Claude Opus 4.1 costs $15.00/M input and $75.00/M output via anthropic.

What are the context window sizes for Claude 3.5 Sonnet and Claude Opus 4.1?

Claude 3.5 Sonnet supports 200K tokens and Claude Opus 4.1 supports 200K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude 3.5 Sonnet and Claude Opus 4.1?

Key differences include LLM Stats Score (19.1 vs 29.9), input pricing ($3.00 vs $15.00/M). See the full comparison above for benchmark-by-benchmark results.