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Claude Opus 4.1 vs Step-3.5-Flash

Both models are evenly matched across the benchmarks. Step-3.5-Flash is 171.4x cheaper per token.

Anthropic · StepFun · Updated for 2026

Which is better?

Claude Opus 4.1 outperforms in 1 benchmarks (SWE-Bench Verified), while Step-3.5-Flash is better at 1 benchmark (AIME 2025). Both models are evenly matched across the benchmarks.

On price, Step-3.5-Flash is roughly 171.4x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Opus 4.1 also accepts a larger context window (200,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current benchmark, pricing, and model metadata for 2026.

Choose Claude Opus 4.1

  • you process long inputs — it offers a 200,000 token context window

Choose Step-3.5-Flash

  • cost matters — it's about 171.4x cheaper per token
  • you want the most recent training data — it shipped Feb 2026
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Opus 4.1
Anthropic
Step-3.5-Flash
StepFun
Benchmark wins
1 of 2
1 of 2
Input price
$15.00 / M
$0.10 / M
Output price
$75.00 / M
$0.40 / M
Context window
200,000
65,536
Released
Aug 2025
Feb 2026
License
Proprietary
Apache 2.0

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Opus 4.1 outperforms in 1 benchmarks (SWE-Bench Verified), while Step-3.5-Flash is better at 1 benchmark (AIME 2025).

Both models are evenly matched across the benchmarks.

Mon Aug 24 2026 • llm-stats.com

Arena Performance

Playground indexes and blind preference scores

Pricing Analysis

Price comparison per million tokens

Step-3.5-Flash costs less

For input processing, Claude Opus 4.1 ($15.00/1M tokens) is 150.0x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, Claude Opus 4.1 ($75.00/1M tokens) is 187.5x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, Claude Opus 4.1 is more expensive than Step-3.5-Flash.*

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

Lowest available price from all providers
Mon Aug 24 2026 • llm-stats.com
Anthropic
Claude Opus 4.1
Input tokens$15.00
Output tokens$75.00
Best providerAnthropic
StepFun
Step-3.5-Flash
Input tokens$0.10
Output tokens$0.40
Best providerStepFun
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Opus 4.1 accepts 200,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. Claude Opus 4.1 can generate longer responses up to 32,000 tokens, while Step-3.5-Flash is limited to 8,192 tokens.

Anthropic
Claude Opus 4.1
Input200,000 tokens
Output32,000 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Mon Aug 24 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 4.1 supports multimodal inputs, whereas Step-3.5-Flash does not.

Claude Opus 4.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 4.1

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 4.1 is licensed under a proprietary license, while Step-3.5-Flash uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Opus 4.1

Proprietary

Closed source

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

Claude Opus 4.1 was released on 2025-08-05, while Step-3.5-Flash was released on 2026-02-02.

Step-3.5-Flash is 6 months newer than Claude Opus 4.1.

Claude Opus 4.1

Aug 5, 2025

1.1 years ago

Step-3.5-Flash

Feb 2, 2026

6 months ago

6mo 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 Opus 4.1 is available from Anthropic, Bedrock, Google. Step-3.5-Flash is available from StepFun.

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

Step-3.5-Flash

stepfun logo
StepFun
Input Price:Input: $0.10/1MOutput Price:Output: $0.40/1M
* 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 Opus 4.1 and Step-3.5-Flash side-by-side, then vote on the output you prefer.

Claude Opus 4.1
✓ Preferred
Step-3.5-Flash
Open in Playground

FAQ

Common questions about Claude Opus 4.1 vs Step-3.5-Flash.

Which is better, Claude Opus 4.1 or Step-3.5-Flash?

Both models are evenly matched across the benchmarks. Claude Opus 4.1 is made by Anthropic and Step-3.5-Flash is made by StepFun. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Opus 4.1 compare to Step-3.5-Flash in benchmarks?

Claude Opus 4.1 scores MMMLU: 89.5%, TAU-bench Retail: 82.4%, GPQA: 80.9%, AIME 2025: 78.0%, MMMU (validation): 77.1%. Step-3.5-Flash scores AIME 2025: 97.3%, Tau-bench: 88.2%, LiveCodeBench v6: 86.4%, IMO-AnswerBench: 85.4%, SWE-Bench Verified: 74.4%.

Is Claude Opus 4.1 cheaper than Step-3.5-Flash?

Step-3.5-Flash is 150.0x cheaper for input tokens. Claude Opus 4.1 costs $15.00/M input and $75.00/M output via anthropic. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.

What are the context window sizes for Claude Opus 4.1 and Step-3.5-Flash?

Claude Opus 4.1 supports 200K tokens and Step-3.5-Flash supports 66K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 4.1 and Step-3.5-Flash?

Key differences include context window (200K vs 66K), input pricing ($15.00 vs $0.10/M), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 4.1 and Step-3.5-Flash?

Claude Opus 4.1 is developed by Anthropic and Step-3.5-Flash is developed by StepFun.

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