Model Comparison

Grok 4.5 vs Step-3.5-FlashWhich is better in 2026?

Comparing Grok 4.5 and Step-3.5-Flash across benchmarks, pricing, and capabilities.

Verdict: Grok 4.5 vs Step-3.5-Flash — which is better?

Grok 4.5 (by xAI) and Step-3.5-Flash (by StepFun) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

On price, Step-3.5-Flash is roughly 17.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Grok 4.5 also accepts a larger context window (500,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Grok 4.5 if…

  • you process long inputs — it offers a 500,000 token context window
  • you want the most recent training data — it shipped Jul 2026

Choose Step-3.5-Flash if…

  • cost matters — it's about 17.1x cheaper per token
  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Grok 4.5 and Step-3.5-Flashdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Step-3.5-Flash costs less

For input processing, Grok 4.5 ($2.00/1M tokens) is 20.0x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, Grok 4.5 ($6.00/1M tokens) is 15.0x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, Grok 4.5 is more expensive than Step-3.5-Flash.*

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

Lowest available price from all providers
Tue Jul 21 2026 • llm-stats.com
xAI
Grok 4.5
Input tokens$2.00
Output tokens$6.00
Best providerxAI
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

Grok 4.5 accepts 500,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. Only Step-3.5-Flash specifies output context (8,192 tokens).

xAI
Grok 4.5
Input500,000 tokens
Output- tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Tue Jul 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Grok 4.5 supports multimodal inputs, whereas Step-3.5-Flash does not.

Grok 4.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Grok 4.5

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

Grok 4.5 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.

Grok 4.5

Proprietary

Closed source

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

Grok 4.5 was released on 2026-07-16, while Step-3.5-Flash was released on 2026-02-02.

Grok 4.5 is 5 months newer than Step-3.5-Flash.

Grok 4.5

Jul 16, 2026

5 days ago

5mo newer
Step-3.5-Flash

Feb 2, 2026

5 months ago

Knowledge Cutoff

When training data ends

Grok 4.5 has a documented knowledge cutoff of 2026-02-01, while Step-3.5-Flash's cutoff date is not specified.

We can confirm Grok 4.5's training data extends to 2026-02-01, but cannot make a direct comparison without Step-3.5-Flash's cutoff date.

Grok 4.5

Feb 2026

Step-3.5-Flash

—

Provider Availability

Grok 4.5 is available from xAI. Step-3.5-Flash is available from StepFun.

Grok 4.5

xai logo
xAI
Input Price:Input: $2.00/1MOutput Price:Output: $6.00/1M

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→

Key Takeaways

xAI
Larger context window (500,000 tokens)
Supports multimodal inputs
StepFun
Less expensive input tokens
Less expensive output tokens
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok 4.5 and Step-3.5-Flash side-by-side, then vote on the output you prefer.

Grok 4.5
✓ Preferred
Step-3.5-Flash
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok 4.5
StepFun
Step-3.5-Flash

FAQ

Common questions about Grok 4.5 vs Step-3.5-Flash.

Which is better, Grok 4.5 or Step-3.5-Flash?

Grok 4.5 (xAI) and Step-3.5-Flash (StepFun) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Grok 4.5 compare to Step-3.5-Flash in benchmarks?

Grok 4.5 scores GPQA: 93.0%, Terminal-Bench 2.1: 83.3%, Artificial Analysis Coding Agent Index v1.1: 76.0%, SWE-Bench Pro: 64.7%, AA-Omniscience Index: 63.0%. 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 Grok 4.5 cheaper than Step-3.5-Flash?

Step-3.5-Flash is 20.0x cheaper for input tokens. Grok 4.5 costs $2.00/M input and $6.00/M output via xai. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.

What are the context window sizes for Grok 4.5 and Step-3.5-Flash?

Grok 4.5 supports 500K 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 Grok 4.5 and Step-3.5-Flash?

Key differences include context window (500K vs 66K), input pricing ($2.00 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 Grok 4.5 and Step-3.5-Flash?

Grok 4.5 is developed by xAI and Step-3.5-Flash is developed by StepFun.

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