Model Comparison

Grok-4 Fast Non-Reasoning vs Grok 4.5Which is better in 2026?

Comparing Grok-4 Fast Non-Reasoning and Grok 4.5 across benchmarks, pricing, and capabilities.

Verdict: Grok-4 Fast Non-Reasoning vs Grok 4.5 — which is better?

Grok-4 Fast Non-Reasoning (by xAI) and Grok 4.5 (by xAI) 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, Grok-4 Fast Non-Reasoning is roughly 10.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Grok-4 Fast Non-Reasoning also accepts a larger context window (2,000,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Grok-4 Fast Non-Reasoning if…

  • cost matters — it's about 10.9x cheaper per token
  • you process long inputs — it offers a 2,000,000 token context window

Choose Grok 4.5 if…

  • you want the most recent training data — it shipped Jul 2026

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Grok-4 Fast Non-Reasoning and Grok 4.5don'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

Grok-4 Fast Non-Reasoning costs less

For input processing, Grok-4 Fast Non-Reasoning ($0.20/1M tokens) is 10.0x cheaper than Grok 4.5 ($2.00/1M tokens).

For output processing, Grok-4 Fast Non-Reasoning ($0.50/1M tokens) is 12.0x cheaper than Grok 4.5 ($6.00/1M tokens).

In conclusion, Grok 4.5 is more expensive than Grok-4 Fast Non-Reasoning.*

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

Lowest available price from all providers
Sun Jul 26 2026 • llm-stats.com
xAI
Grok-4 Fast Non-Reasoning
Input tokens$0.20
Output tokens$0.50
Best providerxAI
xAI
Grok 4.5
Input tokens$2.00
Output tokens$6.00
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Grok-4 Fast Non-Reasoning accepts 2,000,000 input tokens compared to Grok 4.5's 500,000 tokens. Only Grok-4 Fast Non-Reasoning specifies output context (30,000 tokens).

xAI
Grok-4 Fast Non-Reasoning
Input2,000,000 tokens
Output30,000 tokens
xAI
Grok 4.5
Input500,000 tokens
Output- tokens
Sun Jul 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Grok-4 Fast Non-Reasoning and Grok 4.5 support multimodal inputs.

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

Grok-4 Fast Non-Reasoning

Text
Images
Audio
Video

Grok 4.5

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.

Grok-4 Fast Non-Reasoning

Proprietary

Closed source

Grok 4.5

Proprietary

Closed source

Release Timeline

When each model was launched

Grok-4 Fast Non-Reasoning was released on 2025-08-28, while Grok 4.5 was released on 2026-07-16.

Grok 4.5 is 11 months newer than Grok-4 Fast Non-Reasoning.

Grok-4 Fast Non-Reasoning

Aug 28, 2025

11 months ago

Grok 4.5

Jul 16, 2026

1 weeks ago

10mo newer

Knowledge Cutoff

When training data ends

Grok 4.5 has a documented knowledge cutoff of 2026-02-01, while Grok-4 Fast Non-Reasoning'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 Grok-4 Fast Non-Reasoning's cutoff date.

Grok-4 Fast Non-Reasoning

—

Grok 4.5

Feb 2026

Provider Availability

Grok-4 Fast Non-Reasoning is available from xAI. Grok 4.5 is available from xAI.

Grok-4 Fast Non-Reasoning

xai logo
xAI
Input Price:Input: $0.20/1MOutput Price:Output: $0.50/1M

Grok 4.5

xai logo
xAI
Input Price:Input: $2.00/1MOutput Price:Output: $6.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

xAI
Larger context window (2,000,000 tokens)
Less expensive input tokens
Less expensive output tokens
xAI

No standout differentiators in the data we have for this pair.

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok-4 Fast Non-Reasoning and Grok 4.5 side-by-side, then vote on the output you prefer.

Grok-4 Fast Non-Reasoning
✓ Preferred
Grok 4.5
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok-4 Fast Non-Reasoning
xAI
Grok 4.5

FAQ

Common questions about Grok-4 Fast Non-Reasoning vs Grok 4.5.

Which is better, Grok-4 Fast Non-Reasoning or Grok 4.5?

Grok-4 Fast Non-Reasoning (xAI) and Grok 4.5 (xAI) 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 Fast Non-Reasoning compare to Grok 4.5 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%.

Is Grok-4 Fast Non-Reasoning cheaper than Grok 4.5?

Grok-4 Fast Non-Reasoning is 10.0x cheaper for input tokens. Grok-4 Fast Non-Reasoning costs $0.20/M input and $0.50/M output via xai. Grok 4.5 costs $2.00/M input and $6.00/M output via xai.

What are the context window sizes for Grok-4 Fast Non-Reasoning and Grok 4.5?

Grok-4 Fast Non-Reasoning supports 2.0M tokens and Grok 4.5 supports 500K 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 Fast Non-Reasoning and Grok 4.5?

Key differences include context window (2.0M vs 500K), input pricing ($0.20 vs $2.00/M). See the full comparison above for benchmark-by-benchmark results.

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