Model Comparison

Grok 4.5 vs o3Which is better in 2026?

Grok 4.5 significantly outperforms across most benchmarks. Grok 4.5 is 1.2x cheaper per token.

Verdict: Grok 4.5 vs o3 — which is better?

Grok 4.5 (by xAI) and o3 (by OpenAI) 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.

Grok 4.5 outperforms in 1 benchmarks (GPQA), while o3 is better at 0 benchmarks. Grok 4.5 significantly outperforms across most benchmarks.

On price, Grok 4.5 is roughly 1.2x 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 want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • cost matters — it's about 1.2x cheaper per token
  • you process long inputs — it offers a 500,000 token context window
  • you want the most recent training data — it shipped Jul 2026

Choose o3 if…

  • you want predictable pricing at $2.00/M input and $8.00/M output

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Grok 4.5 outperforms in 1 benchmarks (GPQA), while o3 is better at 0 benchmarks.

Grok 4.5 significantly outperforms across most benchmarks.

Tue Jul 21 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Grok 4.5 costs less

For input processing, Grok 4.5 ($2.00/1M tokens) costs the same as o3 ($2.00/1M tokens).

For output processing, Grok 4.5 ($6.00/1M tokens) is 1.3x cheaper than o3 ($8.00/1M tokens).

In conclusion, o3 is more expensive than Grok 4.5.*

* 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
OpenAI
o3
Input tokens$2.00
Output tokens$8.00
Best providerOpenAI
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 o3's 200,000 tokens. Only o3 specifies output context (100,000 tokens).

xAI
Grok 4.5
Input500,000 tokens
Output- tokens
OpenAI
o3
Input200,000 tokens
Output100,000 tokens
Tue Jul 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Grok 4.5 and o3 support multimodal inputs.

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

Grok 4.5

Text
Images
Audio
Video

o3

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 4.5

Proprietary

Closed source

o3

Proprietary

Closed source

Release Timeline

When each model was launched

Grok 4.5 was released on 2026-07-16, while o3 was released on 2025-04-16.

Grok 4.5 is 15 months newer than o3.

Grok 4.5

Jul 16, 2026

4 days ago

1.2yr newer
o3

Apr 16, 2025

1.3 years ago

Knowledge Cutoff

When training data ends

Grok 4.5 has a knowledge cutoff of 2026-02-01, while o3 has a cutoff of 2024-05-31.

Grok 4.5 has more recent training data (up to 2026-02-01), making it potentially better informed about events through that date compared to o3 (2024-05-31).

Grok 4.5

Feb 2026

1.8 yr newer
o3

May 2024

Provider Availability

Grok 4.5 is available from xAI. o3 is available from OpenAI.

Grok 4.5

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

o3

openai logo
OpenAI
Input Price:Input: $2.00/1MOutput Price:Output: $8.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

xAI
Larger context window (500,000 tokens)
Less expensive output tokens
Higher GPQA score (93.0% vs 83.3%)
OpenAI

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

xAIGrok 4.5
OpenAIo3
Compare in Playground

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok 4.5 and o3 side-by-side, then vote on the output you prefer.

Grok 4.5
✓ Preferred
o3
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok 4.5
OpenAI
o3

FAQ

Common questions about Grok 4.5 vs o3.

Which is better, Grok 4.5 or o3?

Grok 4.5 significantly outperforms across most benchmarks. Grok 4.5 is made by xAI and o3 is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Grok 4.5 compare to o3 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%. o3 scores COLLIE: 98.4%, AIME 2024: 91.6%, ARC-AGI: 88.0%, MathVista: 86.8%, AIME 2025: 86.4%.

Is Grok 4.5 cheaper than o3?

Both models cost $2.00 per million input tokens.

What are the context window sizes for Grok 4.5 and o3?

Grok 4.5 supports 500K tokens and o3 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 Grok 4.5 and o3?

Key differences include context window (500K vs 200K). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok 4.5 and o3?

Grok 4.5 is developed by xAI and o3 is developed by OpenAI.

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