# GPT-4.5 vs gpt-oss-120b

> GPT-4.5 and gpt-oss-120b score almost the same on the Noometry Index (37.2 vs 36.3), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/gpt-4-5-vs-gpt-oss-120b
- Last updated: 2026-10-12
- Shared benchmarks: 26

## Summary

- They share 26 benchmarks with published results for both. GPT-4.5 scores higher in 6 categories and gpt-oss-120b in 3 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where gpt-oss-120b leads 52.5 to 32.6.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 37.8% for GPT-4.5 and 88.9% for gpt-oss-120b.
- gpt-oss-120b has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 37.2 | 36.3 |
| Rank | 208 | 217 |
| Context | — | 131K |
| Input $/M | — | $0.037 |
| Output $/M | — | $0.17 |
| Weights | Proprietary | Open |

## Coding

- GPT-4.5: 42.2 (#109)
- gpt-oss-120b: 33.5 (#256)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| Aider Polyglot | 44.9% | 41.8% |
| WeirdML | 39.4% | 48.2% |
| LMArena Coding | 1396 | 1380 |
| SWE-bench Verified (bash only) | — | 26% |
| SciCode | — | 36% |
| LiveBench Coding | 75.2% | — |
| ALE-Bench | — | 575.62 |
| AlgoTune | — | 1.41 |

## Agentic & Tool Use

- GPT-4.5: 27.9 (#97)
- gpt-oss-120b: 12.2 (#153)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| Terminal-Bench | — | 18.7% |
| APEX-Agents | — | 4.4% |
| Cybench | 17.5% | — |
| METR Time Horizons | — | 56.6% |
| Vending-Bench 2 | — | -21.53 |

## Reasoning

- GPT-4.5: 13.9 (#330)
- gpt-oss-120b: 20.0 (#245)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| SimpleBench | 34.5% | 22.1% |
| LMArena Hard Prompts | 1403 | 1364 |
| Epoch Capabilities Index | 136.74 | 139.93 |
| ARC-AGI-2 | 0.8% | — |
| Kagi LLM Benchmark | — | 58.6% |
| ARC-AGI-1 | 10.3% | — |
| CritPt | — | 1.1% |
| Chess Puzzles | — | 20% |
| EnigmaEval | 3.2% | — |
| LiveBench Reasoning | 71.1% | — |
| Mystery Game Puzzles | — | 2% |
| DTBench | — | 76.3% |
| LiveBench Data Analysis | 64.3% | — |
| LMCA | — | 22.1% |
| Surface Evolver Bench | — | 25% |
| ForecastBench | 61.7 | — |
| LiveBench | 69% | — |

## Math

- GPT-4.5: 32.6 (#211)
- gpt-oss-120b: 52.5 (#50)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 37.8% | 88.9% |
| LMArena Math | 1412 | 1389 |
| Omni-MATH | — | 68.8% |
| LiveBench Math | 69.3% | — |
| MATH Level 5 | 78.6% | — |

## Knowledge

- GPT-4.5: 32.5 (#211)
- gpt-oss-120b: 42.4 (#96)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| GPQA Diamond | 68.7% | 75.8% |
| Confabulations | 13.6% | 15.7% |
| LMArena Expert | 1394 | 1356 |
| Humanity's Last Exam | 5.4% | — |
| MMLU-Pro | — | 79.5% |
| Vectara Hallucination Rate | — | 14.2% |
| GPQA (HELM) | — | 68.4% |

## Multimodal

- GPT-4.5: 37.6 (#71)
- gpt-oss-120b: —

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| LMArena Vision | 1195 | — |
| VPCT | 45% | — |

## Multilingual

- GPT-4.5: 52.5 (#83)
- gpt-oss-120b: 48.0 (#147)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| LMArena Non-English | 1413 | 1351 |
| LMArena Chinese | 1421 | 1385 |
| LMArena French | 1418 | 1369 |
| LMArena German | 1457 | 1353 |
| LMArena Japanese | 1416 | 1331 |
| LMArena Korean | 1392 | 1282 |
| LMArena Russian | 1419 | 1343 |
| LMArena Spanish | — | 1389 |

## Instruction Following

- GPT-4.5: 72.6 (#134)
- gpt-oss-120b: 69.3 (#173)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| LMArena Instruction Following | 1404 | 1318 |
| LiveBench Instruction Following | 72.3% | — |
| IFEval | — | 83.6% |

## Long Context

- GPT-4.5: 40.4 (#155)
- gpt-oss-120b: 31.4 (#278)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| Fiction.LiveBench | 63.9% | 44.4% |
| LMArena Longer Query | 1406 | 1319 |

## Writing & Preference

- GPT-4.5: 56.9 (#134)
- gpt-oss-120b: 46.5 (#217)

| Benchmark | GPT-4.5 | gpt-oss-120b |
|---|---|---|
| LMArena Text | 1417 | 1365 |
| LMArena Creative Writing | 1394 | 1275 |
| Short-Story Creative Writing | 75.6% | 77.1% |
| EQ-Bench Creative Writing | 1258 | 961 |
| LMArena Multi-Turn | 1444 | 1340 |
| WildBench | — | 84.5% |
| LiveBench Language | 61.5% | — |

## FAQ

### Is GPT-4.5 better than gpt-oss-120b?

GPT-4.5 and gpt-oss-120b score almost the same on the Noometry Index (37.2 vs 36.3), so choose on price, context window or the category you care about most.

### Is GPT-4.5 or gpt-oss-120b better for coding?

GPT-4.5 scores higher on coding benchmarks: 42.2 versus 33.5 in the Noometry coding category.

### How many benchmarks do GPT-4.5 and gpt-oss-120b share?

26 benchmarks have published results for both models. GPT-4.5 has 42 scored results on Noometry and gpt-oss-120b has 48.