# GPT-5.3 Chat vs Grok 4.3

> Grok 4.3 is the stronger model overall, scoring 43.6 to 42.1 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-3-chat-vs-grok-4-3
- Last updated: 2026-10-10
- Shared benchmarks: 17

## Summary

- They share 17 benchmarks with published results for both. GPT-5.3 Chat scores higher in 3 categories and Grok 4.3 in 5 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Grok 4.3 leads 52.5 to 38.2.
- Grok 4.3 is cheaper at $1.25 / $2.50 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
- Grok 4.3 accepts more context: 1M tokens versus 128K.

## Snapshot

| | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 42.1 | 43.6 |
| Rank | 109 | 80 |
| Context | 128K | 1M |
| Input $/M | $1.75 | $1.25 |
| Output $/M | $14 | $2.50 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.3 Chat: 40.8 (#124)
- Grok 4.3: 41.3 (#117)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Coding | 1408 | 1415 |
| LMArena WebDev | — | 1357 |
| SciCode | — | 47.3% |
| WeirdML | — | 49.9% |
| ALE-Bench | — | 944.17 |

## Agentic & Tool Use

- GPT-5.3 Chat: —
- Grok 4.3: 27.6 (#93)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| GDP.pdf | — | 8% |
| LMArena Search | — | 1165 |
| Vending-Bench 2 | — | 35.26 |

## Reasoning

- GPT-5.3 Chat: 27.3 (#105)
- Grok 4.3: 34.9 (#60)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Hard Prompts | 1399 | 1397 |
| NYT Connections (extended) | — | 55.2% |
| CritPt | — | 8% |
| Chess Puzzles | — | 25% |
| DTBench | — | 90.7% |
| LMCA | — | 38.3% |
| Epoch Capabilities Index | — | 149.13 |
| ForecastBench | — | 60.3 |

## Math

- GPT-5.3 Chat: 35.4 (#146)
- Grok 4.3: 45.8 (#60)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Math | 1389 | 1388 |
| FrontierMath (Tiers 1-3) | — | 42.8% |
| FrontierMath Tier 4 | — | 14.6% |
| OTIS Mock AIME 2024-2025 | — | 93.3% |
| ProofBench | — | 11% |

## Knowledge

- GPT-5.3 Chat: 38.2 (#137)
- Grok 4.3: 52.5 (#57)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Expert | 1397 | 1385 |
| GPQA Diamond | — | 88.8% |
| SimpleQA Verified | — | 33.2% |

## Multimodal

- GPT-5.3 Chat: —
- Grok 4.3: 31.6 (#96)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Vision | — | 1231 |
| Blueprint-Bench 2 | — | 0% |

## Multilingual

- GPT-5.3 Chat: 50.5 (#119)
- Grok 4.3: 50.7 (#114)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Non-English | 1383 | 1385 |
| LMArena Chinese | 1433 | 1423 |
| LMArena French | 1398 | 1412 |
| LMArena German | 1384 | 1395 |
| LMArena Japanese | 1351 | 1379 |
| LMArena Korean | 1347 | 1357 |
| LMArena Russian | 1400 | 1399 |
| LMArena Spanish | 1371 | 1402 |

## Instruction Following

- GPT-5.3 Chat: 73.0 (#124)
- Grok 4.3: 72.3 (#135)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Instruction Following | 1378 | 1366 |

## Long Context

- GPT-5.3 Chat: 42.6 (#115)
- Grok 4.3: 42.5 (#118)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Longer Query | 1396 | 1393 |

## Writing & Preference

- GPT-5.3 Chat: 63.3 (#65)
- Grok 4.3: 58.6 (#112)

| Benchmark | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| LMArena Text | 1389 | 1397 |
| LMArena Creative Writing | 1356 | 1380 |
| LMArena Multi-Turn | 1413 | 1406 |
| EQ-Bench Creative Writing | 1690 | — |
| EQ-Bench 4 | — | 1075 |

## FAQ

### Is GPT-5.3 Chat better than Grok 4.3?

Grok 4.3 is the stronger model overall, scoring 43.6 to 42.1 on the Noometry Index.

### Which is cheaper, GPT-5.3 Chat or Grok 4.3?

Grok 4.3 is cheaper. It lists at $1.25 per million input tokens and $2.50 per million output tokens; GPT-5.3 Chat lists at $1.75 and $14.

### Is GPT-5.3 Chat or Grok 4.3 better for coding?

They score almost the same on coding (40.8 vs 41.3); test both on your own repository before choosing.

### Which has the bigger context window?

Grok 4.3 does, with 1M tokens against 128K.

### How many benchmarks do GPT-5.3 Chat and Grok 4.3 share?

17 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Grok 4.3 has 40.