Claude Opus 4.5 vs GPT-5.1
At a Glance
| Compare | Claude Opus 4.5Anthropic |  GPT-5.1OpenAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | #27 of 4655.4 score · 2/3 sources · provisional · missing ARC-AGI-2 · full-core range 36.9–70.3 | #37 of 4625.7 score · 2/3 sources · provisional · missing LiveBench · full-core range 17.1–50.5 |
| CostLower is better · Published-token output estimate | #40 of 44$0.380 per LiveBench case | UnrankedNot in the 44-model eligible cohort |
| EfficiencyHigher is better · MM Efficiency v1.5 | #36 of 3838.0 score · 2/3 sources · provisional · missing ARC-AGI-2 · full-core range 28.8–45.4 | UnrankedNot in the 38-model eligible cohort |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $5.00Anthropic ↗ · Sep 3, 2026 | $1.25Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $25.00Anthropic ↗ · Sep 3, 2026 | $10.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 200K | 400K |
| Model facts checked | Sep 3, 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 | Claude Opus 4.5 | GPT-5.1 |
|---|---|---|
| LMArena Document Arenadocument-2026-09-13-d25aabda0010 · arena_rating · leader | 1,462.20100% of row best · rating · claude-opus-4-5-20251101; 95% CI [1451.78988580, 1472.60655272]; votes 7981; rank 21 | 1,403.1796% of row best · rating · gpt-5.1; 95% CI [1393.82886201, 1412.50542979]; votes 8244; rank 42 |
| LMArena Search Arenasearch-2026-08-24-d25aabda0010 · arena_rating · leader | 1,179.6498% of row best · rating · claude-opus-4-5-search; 95% CI [1174.02872051, 1185.26030035]; votes 61573; rank 19 | 1,199.44100% of row best · rating · gpt-5.1-search; 95% CI [1194.20592738, 1204.68165473]; votes 59909; rank 14 |
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · leader | 1,447.08100% of row best · rating · claude-opus-4-5-20251101-high-32k; 95% CI [1443.17965746, 1450.98398333]; votes 36239; rank 49 | 1,422.5798% of row best · rating · gpt-5.1; 95% CI [1418.95842118, 1426.18777801]; votes 42982; rank 100 |
| Overall ResultCounted from the protocol-matched rows above | 2 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 | Claude Opus 4.5 | GPT-5.1 |
|---|---|---|
| Developer | Anthropic | OpenAI |
| Family | Claude 4 | Gpt 5 1 |
| Model | Claude Opus 4.5 | GPT-5.1 |
| Version | Claude Opus 4.5 | GPT-5.1 |
| Lifecycle | active | active |
| Released | 2025-11-24 | 2025-11-13 |
| Knowledge cutoff | 2025-05-01 | 2024-09-30 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 200K | 400K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Anthropic (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
Claude Opus 4.5 Capabilities
GPT-5.1 Capabilities
Related Comparisons
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|---|---|---|---|
Claude Opus 4.5Anthropic | vs | GPT-6 AstraOpenAI | cross-developer peersimage, text |
Claude Fable 5.1Anthropic | vs | Claude Opus 4.5Anthropic | family variantsimage, text |
Claude Opus 4.5Anthropic | vs |  Gemini 3.1 ProGoogle DeepMind | cross-developer peerstext |
Claude Opus 4.5Anthropic | vs |  DeepSeek-V4.1-FlashDeepSeek | cross-developer peersimage, text |
Claude Opus 4.5Anthropic | vs | Grok 4.6xAI | cross-developer peersimage, text |
Claude Opus 4.5Anthropic | vs |  Qwen3.8-MaxQwen | cross-developer peersimage, text |
Claude Opus 4.5Anthropic | vs |  Kimi-K3Moonshot AI | cross-developer peersimage, text |
 MiniMax-M3MiniMax | vs | Claude Opus 4.5Anthropic | cross-developer peersimage, text |
Claude Opus 4.5Anthropic | vs |  GLM-5.3Z.ai | cross-developer peerstext |
Claude Opus 4.5Anthropic | vs |  Hy4 previewTencent | cross-developer peerstext |
Claude Opus 4.5Anthropic | vs | Seed 2.1 ProByteDance Seed | cross-developer peersimage, text |
Claude Opus 4.5Anthropic | vs |  Mistral Large 3Mistral AI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Opus 4.5 vs GPT-5.1 FAQs
Is Claude Opus 4.5 or GPT-5.1 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Opus 4.5 and GPT-5.1, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Opus 4.5 or GPT-5.1?+
Claude Opus 4.5 is $5.00 and GPT-5.1 is $1.25 per million tokens, so GPT-5.1 is cheaper on this metric. Claude Opus 4.5 is $25.00 and GPT-5.1 is $10.00 per million tokens, so GPT-5.1 is cheaper on this metric.
Which has a larger context window, Claude Opus 4.5 or GPT-5.1?+
GPT-5.1 has the larger sourced context window. Claude Opus 4.5 supports 200K and GPT-5.1 supports 400K.
Which performs better in benchmarks, Claude Opus 4.5 or GPT-5.1?+
There is no overall benchmark winner: An overall winner requires at least two decisive benchmarks from at least two original publishers.
Can Claude Opus 4.5 or GPT-5.1 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Opus 4.5 is not marked open weight; GPT-5.1 is not marked open weight.
Can Claude Opus 4.5 and GPT-5.1 understand images?+
Claude Opus 4.5 is documented with image input; GPT-5.1 is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Opus 4.5 or GPT-5.1?+
GPT-5.1 has the larger sourced maximum output: Claude Opus 4.5 supports 64K and GPT-5.1 supports 128K output tokens.
Do Claude Opus 4.5 and GPT-5.1 support reasoning and tool use?+
Claude Opus 4.5: reasoning, tool calling, and image input. GPT-5.1: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Opus 4.5 or GPT-5.1?+
Claude Opus 4.5 has 1 sourced provider route; GPT-5.1 has 2, so GPT-5.1 has broader tracked availability.
Which offers better value, Claude Opus 4.5 or GPT-5.1?+
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.