# gpt-oss-20b vs Grok 4.3

> Grok 4.3 is the stronger model overall, scoring 43.6 to 32.1 on the Noometry Index. gpt-oss-20b costs 43× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-oss-20b-vs-grok-4-3
- Last updated: 2026-10-10
- Shared benchmarks: 26

## Summary

- They share 26 benchmarks with published results for both. gpt-oss-20b scores higher in 0 categories and Grok 4.3 in 9 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Grok 4.3 leads 58.6 to 35.8.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 65.3% for gpt-oss-20b and 93.3% for Grok 4.3.
- gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $1.25 / $2.50 for Grok 4.3.
- Grok 4.3 accepts more context: 1M tokens versus 131K.
- gpt-oss-20b has downloadable open weights; the other is API-only.

## Snapshot

| | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 32.1 | 43.6 |
| Rank | 249 | 80 |
| Context | 131K | 1M |
| Input $/M | $0.018 | $1.25 |
| Output $/M | $0.09 | $2.50 |
| Weights | Open | Proprietary |

## Coding

- gpt-oss-20b: 37.1 (#185)
- Grok 4.3: 41.3 (#117)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| SciCode | 34.4% | 47.3% |
| WeirdML | 40.9% | 49.9% |
| LMArena Coding | 1307 | 1415 |
| ALE-Bench | 566.05 | 944.17 |
| LMArena WebDev | — | 1357 |

## Agentic & Tool Use

- gpt-oss-20b: 9.2 (#146)
- Grok 4.3: 27.6 (#93)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| Terminal-Bench | 3.4% | — |
| GDP.pdf | — | 8% |
| LMArena Search | — | 1165 |
| Vending-Bench 2 | — | 35.26 |

## Reasoning

- gpt-oss-20b: 18.8 (#251)
- Grok 4.3: 34.9 (#60)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| CritPt | 1.4% | 8% |
| Chess Puzzles | 4% | 25% |
| LMArena Hard Prompts | 1274 | 1397 |
| DTBench | 68% | 90.7% |
| LMCA | 14.5% | 38.3% |
| Epoch Capabilities Index | 137.81 | 149.13 |
| Kagi LLM Benchmark | 53.2% | — |
| NYT Connections (extended) | — | 55.2% |
| ForecastBench | — | 60.3 |

## Math

- gpt-oss-20b: 37.6 (#93)
- Grok 4.3: 45.8 (#60)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 65.3% | 93.3% |
| LMArena Math | 1317 | 1388 |
| FrontierMath (Tiers 1-3) | — | 42.8% |
| FrontierMath Tier 4 | — | 14.6% |
| ProofBench | — | 11% |
| Omni-MATH | 56.5% | — |

## Knowledge

- gpt-oss-20b: 34.6 (#186)
- Grok 4.3: 52.5 (#57)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| GPQA Diamond | 60.8% | 88.8% |
| LMArena Expert | 1258 | 1385 |
| SimpleQA Verified | — | 33.2% |
| MMLU-Pro | 74% | — |
| GPQA (HELM) | 59.4% | — |

## Multimodal

- gpt-oss-20b: —
- Grok 4.3: 31.6 (#96)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| LMArena Vision | — | 1231 |
| Blueprint-Bench 2 | — | 0% |

## Multilingual

- gpt-oss-20b: 42.4 (#192)
- Grok 4.3: 50.7 (#114)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| LMArena Non-English | 1269 | 1385 |
| LMArena Chinese | 1311 | 1423 |
| LMArena German | 1249 | 1395 |
| LMArena Japanese | 1245 | 1379 |
| LMArena Korean | 1239 | 1357 |
| LMArena Russian | 1279 | 1399 |
| LMArena Spanish | 1267 | 1402 |
| LMArena French | — | 1412 |

## Instruction Following

- gpt-oss-20b: 62.0 (#235)
- Grok 4.3: 72.3 (#135)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| LMArena Instruction Following | 1236 | 1366 |
| IFEval | 73.2% | — |

## Long Context

- gpt-oss-20b: 37.9 (#203)
- Grok 4.3: 42.5 (#118)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| LMArena Longer Query | 1251 | 1393 |

## Writing & Preference

- gpt-oss-20b: 35.8 (#260)
- Grok 4.3: 58.6 (#112)

| Benchmark | gpt-oss-20b | Grok 4.3 |
|---|---|---|
| LMArena Text | 1288 | 1397 |
| LMArena Creative Writing | 1201 | 1380 |
| LMArena Multi-Turn | 1268 | 1406 |
| EQ-Bench Creative Writing | 666 | — |
| WildBench | 73.7% | — |
| EQ-Bench 4 | — | 1075 |

## FAQ

### Is gpt-oss-20b better than Grok 4.3?

Grok 4.3 is the stronger model overall, scoring 43.6 to 32.1 on the Noometry Index. gpt-oss-20b costs 43× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

### Which is cheaper, gpt-oss-20b or Grok 4.3?

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Grok 4.3 lists at $1.25 and $2.50.

### Is gpt-oss-20b or Grok 4.3 better for coding?

Grok 4.3 scores higher on coding benchmarks: 41.3 versus 37.1 in the Noometry coding category.

### Which has the bigger context window?

Grok 4.3 does, with 1M tokens against 131K.

### How many benchmarks do gpt-oss-20b and Grok 4.3 share?

26 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and Grok 4.3 has 40.