gpt-oss-120b vs Grok 4.5
At a Glance
| Compare |  gpt-oss-120bOpenAI | Grok 4.5xAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | UnrankedNot in the 46-model eligible cohort | #25 of 4660.1 score · 3/3 sources · complete |
| CostLower is better · Published-token output estimate | UnrankedNot in the 44-model eligible cohort | #15 of 44$0.063 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.5 | UnrankedNot in the 38-model eligible cohort | #11 of 3859.2 score · 3/3 sources · complete |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $0.037Deepinfra ↗ · Sep 22, 2026 | $2.00Xai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $0.17Deepinfra ↗ · Sep 22, 2026 | $6.00Xai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 131K | 500K |
| Model facts checked | Aug 28, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
| Benchmark | gpt-oss-120b | Grok 4.5 |
|---|---|---|
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · leader | 1,365.8794% of row best · rating · gpt-oss-120b; 95% CI [1361.49487468, 1370.23719284]; votes 29955; rank 176 | 1,450.13100% of row best · rating · grok-4.5; 95% CI [1445.44268767, 1454.81726995]; votes 30103; rank 45 |
| ToneBench2026-09-11-10-task-4ef099199c9c · overall_score · unverified | 68.0183% of row best · points · gpt-oss 120B (high) · 7,577 output tokens / case | 82.23100% of row best · points · Grok 4.5 · 2,688 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 0 benchmark winsNo overall winner | 1 benchmark winNo overall winner |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Side-by-Side Facts
| Field | gpt-oss-120b | Grok 4.5 |
|---|---|---|
| Developer | OpenAI | xAI |
| Family | Gpt Oss 120b | Grok 4 |
| Model | gpt-oss-120b | Grok 4.5 |
| Version | gpt-oss-120b | Grok 4.5 |
| Lifecycle | active | active |
| Released | Unknown | 2026-07-16 |
| Knowledge cutoff | Unknown | Unknown |
| Input modalities | Text | Text, Image |
| Output modalities | Text | Text |
| Context window | 131K | 500K |
| Total parameters | 116.8B | Unknown |
| Active parameters | 5.1B | Unknown |
| License | apache-2.0 | Unknown |
| Open weights | Yes | No |
| API available | Yes | Yes |
| Self-hostable | Yes | No |
| Provider access | Cerebras (Standard), Deepinfra (Standard), Fireworks Ai (Serverless, Standard), Groq (Standard), Hugging Face (Standard), Openrouter (Standard), Together Ai (Serverless, Standard) | Xai (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
gpt-oss-120b Capabilities
Grok 4.5 Capabilities
Related Comparisons
All text comparisons →| A | Pair | B | Context |
|---|---|---|---|
GPT-6 AstraOpenAI | vs | gpt-oss-120bOpenAI | family variantstext |
Claude Fable 5.1Anthropic | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
 Gemini 3.1 ProGoogle DeepMind | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
 DeepSeek-V4.1-FlashDeepSeek | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
gpt-oss-120bOpenAI | vs | Grok 4.6xAI | cross-developer peerstext |
gpt-oss-120bOpenAI | vs |  Qwen3.8-MaxQwen | cross-developer peerstext |
 Kimi-K3Moonshot AI | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
 MiniMax-M3MiniMax | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
gpt-oss-120bOpenAI | vs |  GLM-5.3Z.ai | cross-developer peerstext |
gpt-oss-120bOpenAI | vs |  Hy4 previewTencent | cross-developer peerstext |
Seed 2.1 ProByteDance Seed | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
 Mistral Large 3Mistral AI | vs | gpt-oss-120bOpenAI | cross-developer peerstext |
Primary Evidence
Sources and Freshness
Questions
gpt-oss-120b vs Grok 4.5 FAQs
Is gpt-oss-120b or Grok 4.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both gpt-oss-120b and Grok 4.5, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, gpt-oss-120b or Grok 4.5?+
gpt-oss-120b is $0.037 and Grok 4.5 is $2.00 per million tokens, so gpt-oss-120b is cheaper on this metric. gpt-oss-120b is $0.17 and Grok 4.5 is $6.00 per million tokens, so gpt-oss-120b is cheaper on this metric.
Which has a larger context window, gpt-oss-120b or Grok 4.5?+
Grok 4.5 has the larger sourced context window. gpt-oss-120b supports 131K and Grok 4.5 supports 500K.
Which performs better in benchmarks, gpt-oss-120b or Grok 4.5?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can gpt-oss-120b or Grok 4.5 be self-hosted?+
gpt-oss-120b is the only model in this pair currently marked as self-hostable. gpt-oss-120b is open weight; Grok 4.5 is not marked open weight.
Can gpt-oss-120b and Grok 4.5 understand images?+
gpt-oss-120b is not documented with image input; Grok 4.5 is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, gpt-oss-120b or Grok 4.5?+
Neither has a larger sourced maximum output. gpt-oss-120b is — and Grok 4.5 is —.
Do gpt-oss-120b and Grok 4.5 support reasoning and tool use?+
gpt-oss-120b: reasoning and tool calling. Grok 4.5: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, gpt-oss-120b or Grok 4.5?+
gpt-oss-120b has 7 sourced provider routes; Grok 4.5 has 1, so gpt-oss-120b has broader tracked availability.
Which offers better value, gpt-oss-120b or Grok 4.5?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.