# Grok 4 Fast (Reasoning) vs o3-pro

> Side-by-side benchmark comparison for Grok 4 Fast (Reasoning) and o3-pro across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/grok-4-fast-reasoning-vs-o3-pro
- Last updated: September 4, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for Grok 4 Fast (Reasoning) and o3-pro.

## Summary

- Grok 4 Fast (Reasoning) and o3-pro do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | Grok 4 Fast (Reasoning) | o3-pro |
|----------|----------|----------|
| Creator | xAI | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 2M | 200K |
| Independent public score (not head-to-head) | 54.56 | 49.16 |
| Benchmarks Covered | 1 | 0 |
| Pricing (input/output) | N/A | $20.00 / $80.00 |

## Category Breakdown

### Coding

- Winner: Insufficient shared evidence
- Grok 4 Fast (Reasoning) public-lane score: 43.9 (Estimated · #119/183)
- o3-pro public-lane score: Coming soon

| Benchmark | Grok 4 Fast (Reasoning) | o3-pro | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 0.00% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Grok 4 Fast (Reasoning) public-lane score: 51.1 (Unranked · 1 rankable row)
- o3-pro public-lane score: Coming soon

### Reasoning

- Winner: Insufficient shared evidence
- Grok 4 Fast (Reasoning) public-lane score: 72.1 (Unranked · 2 rankable rows)
- o3-pro public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- Grok 4 Fast (Reasoning) public-lane score: 49.2 (Estimated · #94/181)
- o3-pro public-lane score: 50.2 (Estimated · #90/181)

### Instruction Following

- Winner: Insufficient shared evidence
- Grok 4 Fast (Reasoning) public-lane score: 60 (#70/120)
- o3-pro public-lane score: Coming soon

## FAQ

### Can I compare Grok 4 Fast (Reasoning) and o3-pro on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

- [Grok 4 Fast (Reasoning) vs o3](/compare/grok-4-fast-reasoning-vs-o3)
- [o3-pro vs o3](/compare/o3-vs-o3-pro)
- [Grok 4 Fast (Reasoning) vs o3-mini](/compare/grok-4-fast-reasoning-vs-o3-mini)
- [o3-pro vs o3-mini](/compare/o3-mini-vs-o3-pro)

## Explore More

- [Grok 4 Fast (Reasoning) profile](/models/grok-4-fast-reasoning)
- [o3-pro profile](/models/o3-pro)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)