# GPT-5 Mini vs gpt-oss-120b

> GPT-5 Mini is the stronger model overall, scoring 41.7 to 36.0 on the Noometry Index. gpt-oss-120b costs 9.8× less per token, which makes it the better buy when GPT-5 Mini's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-mini-vs-gpt-oss-120b
- Last updated: 2026-10-10
- Shared benchmarks: 43

## Summary

- They share 43 benchmarks with published results for both. GPT-5 Mini scores higher in 8 categories and gpt-oss-120b in 1 category; 8 gaps are clear of the uncertainty.
- The widest gap is in agentic & tool use, where GPT-5 Mini leads 31.0 to 12.1.
- The biggest single-benchmark swing is SWE-bench Verified (bash only): 59.8% for GPT-5 Mini and 26% for gpt-oss-120b.
- gpt-oss-120b is cheaper at $0.037 / $0.17 per million input/output tokens, against $0.25 / $2 for GPT-5 Mini.
- GPT-5 Mini accepts more context: 400K tokens versus 131K.
- gpt-oss-120b has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 41.7 | 36.0 |
| Rank | 115 | 210 |
| Context | 400K | 131K |
| Input $/M | $0.25 | $0.037 |
| Output $/M | $2 | $0.17 |
| Weights | Proprietary | Open |

## Coding

- GPT-5 Mini: 40.0 (#134)
- gpt-oss-120b: 33.2 (#251)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| SWE-bench Verified (bash only) | 59.8% | 26% |
| SciCode | 39.2% | 36% |
| WeirdML | 52.7% | 48.2% |
| LMArena Coding | 1406 | 1380 |
| ALE-Bench | 799.77 | 575.62 |
| AlgoTune | 1.38 | 1.41 |
| SWE-bench Verified | 64.7% | — |
| Aider Polyglot | — | 41.8% |
| SWE-bench Multilingual | 39.7% | — |

## Agentic & Tool Use

- GPT-5 Mini: 31.0 (#64)
- gpt-oss-120b: 12.1 (#145)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| Terminal-Bench | 34.8% | 18.7% |
| Vending-Bench 2 | -31.18 | -21.53 |
| APEX-Agents | — | 4.4% |
| Berkeley Function Calling Leaderboard | 55.5% | — |
| METR Time Horizons | — | 56.6% |

## Reasoning

- GPT-5 Mini: 24.1 (#153)
- gpt-oss-120b: 19.5 (#236)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| Kagi LLM Benchmark | 70.3% | 58.6% |
| CritPt | 0% | 1.1% |
| Chess Puzzles | 30% | 20% |
| LMArena Hard Prompts | 1380 | 1364 |
| Mystery Game Puzzles | 10% | 2% |
| DTBench | 80.5% | 76.3% |
| LMCA | 34.2% | 22.1% |
| Epoch Capabilities Index | 145.51 | 139.94 |
| ARC-AGI-2 | 4.4% | — |
| SimpleBench | — | 22.1% |
| ARC-AGI-1 | 54.3% | — |
| EnigmaEval | 8.2% | — |
| Surface Evolver Bench | — | 25% |
| ForecastBench | 61 | — |

## Math

- GPT-5 Mini: 46.3 (#59)
- gpt-oss-120b: 50.6 (#43)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 86.7% | 88.9% |
| Omni-MATH | 72.2% | 68.8% |
| LMArena Math | 1377 | 1388 |
| FrontierMath (Tiers 1-3) | 46.7% | — |
| FrontierMath Tier 4 | 12.2% | — |
| ProofBench | 9% | — |
| MATH Level 5 | 97.8% | — |
| FrontierMath (Feb 2025 set) | 27.2% | — |
| FrontierMath Tier 4 (v1) | 6.3% | — |

## Knowledge

- GPT-5 Mini: 45.5 (#80)
- gpt-oss-120b: 42.3 (#89)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| GPQA Diamond | 75% | 75.8% |
| MMLU-Pro | 83.5% | 79.5% |
| Confabulations | 13.3% | 15.7% |
| Vectara Hallucination Rate | 12.9% | 14.2% |
| GPQA (HELM) | 75.6% | 68.4% |
| LMArena Expert | 1377 | 1356 |
| Humanity's Last Exam | 19.4% | — |
| SimpleQA Verified | 21.6% | — |

## Multimodal

- GPT-5 Mini: 35.0 (#80)
- gpt-oss-120b: —

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| LMArena Vision | 1202 | — |
| VPCT | 40.2% | — |

## Multilingual

- GPT-5 Mini: 49.1 (#131)
- gpt-oss-120b: 48.2 (#142)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| LMArena Non-English | 1363 | 1350 |
| LMArena Chinese | 1387 | 1384 |
| LMArena French | 1385 | 1370 |
| LMArena German | 1366 | 1355 |
| LMArena Japanese | 1342 | 1332 |
| LMArena Korean | 1306 | 1283 |
| LMArena Russian | 1362 | 1343 |
| LMArena Spanish | 1355 | 1388 |

## Instruction Following

- GPT-5 Mini: 76.4 (#43)
- gpt-oss-120b: 69.5 (#168)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| IFEval | 92.7% | 83.6% |
| LMArena Instruction Following | 1357 | 1318 |

## Long Context

- GPT-5 Mini: 41.9 (#127)
- gpt-oss-120b: 31.4 (#273)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| Fiction.LiveBench | 69.4% | 44.4% |
| LMArena Longer Query | 1355 | 1319 |

## Writing & Preference

- GPT-5 Mini: 55.4 (#143)
- gpt-oss-120b: 46.7 (#213)

| Benchmark | GPT-5 Mini | gpt-oss-120b |
|---|---|---|
| LMArena Text | 1373 | 1366 |
| LMArena Creative Writing | 1325 | 1274 |
| Short-Story Creative Writing | 83.1% | 77.1% |
| EQ-Bench Creative Writing | 1313 | 961 |
| WildBench | 85.5% | 84.5% |
| LMArena Multi-Turn | 1363 | 1340 |

## FAQ

### Is GPT-5 Mini better than gpt-oss-120b?

GPT-5 Mini is the stronger model overall, scoring 41.7 to 36.0 on the Noometry Index. gpt-oss-120b costs 9.8× less per token, which makes it the better buy when GPT-5 Mini's lead doesn't matter for your workload.

### Which is cheaper, GPT-5 Mini or gpt-oss-120b?

gpt-oss-120b is cheaper. It lists at $0.037 per million input tokens and $0.17 per million output tokens; GPT-5 Mini lists at $0.25 and $2.

### Is GPT-5 Mini or gpt-oss-120b better for coding?

GPT-5 Mini scores higher on coding benchmarks: 40.0 versus 33.2 in the Noometry coding category.

### Which has the bigger context window?

GPT-5 Mini does, with 400K tokens against 131K.

### How many benchmarks do GPT-5 Mini and gpt-oss-120b share?

43 benchmarks have published results for both models. GPT-5 Mini has 60 scored results on Noometry and gpt-oss-120b has 48.