# GPT-5.3 Chat vs Grok 3

> GPT-5.3 Chat is the stronger model overall, scoring 42.1 to 39.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-3-chat-vs-grok-3
- Last updated: 2026-10-10
- Shared benchmarks: 18

## Summary

- They share 18 benchmarks with published results for both. GPT-5.3 Chat scores higher in 3 categories and Grok 3 in 5 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5.3 Chat leads 27.3 to 13.8.

## Snapshot

| | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 42.1 | 39.6 |
| Rank | 109 | 150 |
| Context | 128K | — |
| Input $/M | $1.75 | — |
| Output $/M | $14 | — |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.3 Chat: 40.8 (#124)
- Grok 3: 41.5 (#113)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Coding | 1408 | 1432 |
| Aider Polyglot | — | 53.3% |
| WeirdML | — | 37.2% |

## Agentic & Tool Use

- GPT-5.3 Chat: —
- Grok 3: 30.2 (#69)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| BALROG | — | 29.5% |

## Reasoning

- GPT-5.3 Chat: 27.3 (#105)
- Grok 3: 13.8 (#322)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Hard Prompts | 1399 | 1433 |
| ARC-AGI-2 | — | 0% |
| SimpleBench | — | 36.1% |
| Kagi LLM Benchmark | — | 61.3% |
| ARC-AGI-1 | — | 5.5% |
| Epoch Capabilities Index | — | 138.34 |

## Math

- GPT-5.3 Chat: 35.4 (#146)
- Grok 3: 36.2 (#122)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Math | 1389 | 1390 |
| OTIS Mock AIME 2024-2025 | — | 55.6% |
| Omni-MATH | — | 46.4% |
| MATH Level 5 | — | 88.7% |
| FrontierMath (Feb 2025 set) | — | 3.8% |
| FrontierMath Tier 4 (v1) | — | 0% |

## Knowledge

- GPT-5.3 Chat: 38.2 (#137)
- Grok 3: 46.0 (#76)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Expert | 1397 | 1420 |
| GPQA Diamond | — | 75.8% |
| MMLU-Pro | — | 78.8% |
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 5.8% |
| GPQA (HELM) | — | 65% |

## Multilingual

- GPT-5.3 Chat: 50.5 (#119)
- Grok 3: 52.5 (#81)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Non-English | 1383 | 1411 |
| LMArena Chinese | 1433 | 1448 |
| LMArena French | 1398 | 1460 |
| LMArena German | 1384 | 1431 |
| LMArena Japanese | 1351 | 1389 |
| LMArena Korean | 1347 | 1374 |
| LMArena Russian | 1400 | 1416 |
| LMArena Spanish | 1371 | 1417 |

## Instruction Following

- GPT-5.3 Chat: 73.0 (#124)
- Grok 3: 75.2 (#69)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Instruction Following | 1378 | 1409 |
| IFEval | — | 88.4% |

## Long Context

- GPT-5.3 Chat: 42.6 (#115)
- Grok 3: 38.7 (#187)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Longer Query | 1396 | 1439 |
| Fiction.LiveBench | — | 58.3% |

## Writing & Preference

- GPT-5.3 Chat: 63.3 (#65)
- Grok 3: 56.0 (#136)

| Benchmark | GPT-5.3 Chat | Grok 3 |
|---|---|---|
| LMArena Text | 1389 | 1426 |
| LMArena Creative Writing | 1356 | 1414 |
| EQ-Bench Creative Writing | 1690 | 1186 |
| LMArena Multi-Turn | 1413 | 1424 |
| Short-Story Creative Writing | — | 76.4% |
| WildBench | — | 84.9% |

## FAQ

### Is GPT-5.3 Chat better than Grok 3?

GPT-5.3 Chat is the stronger model overall, scoring 42.1 to 39.6 on the Noometry Index.

### Is GPT-5.3 Chat or Grok 3 better for coding?

They score almost the same on coding (40.8 vs 41.5); test both on your own repository before choosing.

### How many benchmarks do GPT-5.3 Chat and Grok 3 share?

18 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Grok 3 has 40.