Kimi K2.5 vs GPT-5.1
At a Glance
| Compare |  Kimi K2.5Moonshot AI |  GPT-5.1OpenAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | UnrankedNot in the 46-model eligible cohort | #37 of 4625.7 score · 2/3 sources · provisional · missing LiveBench · full-core range 17.1–50.5 |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $0.45Deepinfra ↗ · Aug 29, 2026 | $1.25Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $2.25Deepinfra ↗ · Aug 29, 2026 | $10.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 262K | 400K |
| 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 | Kimi-K2.5 | GPT-5.1 |
|---|---|---|
| LMArena Document Arenadocument-2026-09-13-d25aabda0010 · arena_rating · leader | 1,430.10100% of row best · rating · kimi-k2.5-thinking; 95% CI [1423.37027866, 1436.81983378]; votes 21569; rank 34 | 1,403.1798% of row best · rating · gpt-5.1; 95% CI [1393.82886201, 1412.50542979]; votes 8244; rank 42 |
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · leader | 1,445.64100% of row best · rating · kimi-k2.5-thinking; 95% CI [1442.30343195, 1448.97544647]; votes 70513; rank 53 | 1,422.5798% of row best · rating · gpt-5.1; 95% CI [1418.95842118, 1426.18777801]; votes 42982; rank 100 |
| LMArena Vision Arenavision-2026-09-13-d25aabda0010 · arena_rating · leader | 1,266.99100% of row best · rating · kimi-k2.5-thinking; 95% CI [1261.13170482, 1272.84453452]; votes 26646; rank 39 | 1,235.0897% of row best · rating · gpt-5.1; 95% CI [1227.35514387, 1242.80648733]; votes 10205; rank 65 |
| Overall ResultCounted from the protocol-matched rows above | 3 benchmark winsNo overall winner | 0 benchmark winsNo 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 | Kimi-K2.5 | GPT-5.1 |
|---|---|---|
| Developer | Moonshot AI | OpenAI |
| Family | Kimi K2 5 | Gpt 5 1 |
| Model | Kimi-K2.5 | GPT-5.1 |
| Version | Kimi-K2.5 | GPT-5.1 |
| Lifecycle | active | active |
| Released | 2026-01-27 | 2025-11-13 |
| Knowledge cutoff | Unknown | 2024-09-30 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 262K | 400K |
| Total parameters | 1T | Unknown |
| Active parameters | 32B | Unknown |
| License | other | Unknown |
| Open weights | Yes | No |
| API available | Yes | Yes |
| Self-hostable | Yes | No |
| Provider access | Deepinfra (Standard), Hugging Face (Standard), Openrouter (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
Kimi K2.5 Capabilities
GPT-5.1 Capabilities
Related Comparisons
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|---|---|---|---|
Kimi-K2.5Moonshot AI | vs | GPT-6 AstraOpenAI | cross-developer peersimage, text |
Claude Fable 5.1Anthropic | vs | Kimi-K2.5Moonshot AI | cross-developer peersimage, text |
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 DeepSeek-V4.1-FlashDeepSeek | vs | Kimi-K2.5Moonshot AI | cross-developer peersimage, text |
Kimi-K2.5Moonshot AI | vs | Grok 4.6xAI | cross-developer peersimage, text |
Kimi-K2.5Moonshot AI | vs |  Qwen3.8-MaxQwen | cross-developer peersimage, text |
Kimi-K2.5Moonshot AI | vs | Kimi-K3Moonshot AI | family variantsembedding, image, text |
 MiniMax-M3MiniMax | vs | Kimi-K2.5Moonshot AI | cross-developer peersimage, text |
Kimi-K2.5Moonshot AI | vs |  GLM-5.3Z.ai | cross-developer peerstext |
Kimi-K2.5Moonshot AI | vs |  Hy4 previewTencent | cross-developer peerstext |
Seed 2.1 ProByteDance Seed | vs | Kimi-K2.5Moonshot AI | cross-developer peersimage, text |
 Mistral Large 3Mistral AI | vs | Kimi-K2.5Moonshot AI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Kimi K2.5 vs GPT-5.1 FAQs
Is Kimi K2.5 or GPT-5.1 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Kimi K2.5 and GPT-5.1, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Kimi K2.5 or GPT-5.1?+
Kimi K2.5 is $0.45 and GPT-5.1 is $1.25 per million tokens, so Kimi K2.5 is cheaper on this metric. Kimi K2.5 is $2.25 and GPT-5.1 is $10.00 per million tokens, so Kimi K2.5 is cheaper on this metric.
Which has a larger context window, Kimi K2.5 or GPT-5.1?+
GPT-5.1 has the larger sourced context window. Kimi K2.5 supports 262K and GPT-5.1 supports 400K.
Which performs better in benchmarks, Kimi K2.5 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 Kimi K2.5 or GPT-5.1 be self-hosted?+
Kimi K2.5 is the only model in this pair currently marked as self-hostable. Kimi K2.5 is open weight; GPT-5.1 is not marked open weight.
Can Kimi K2.5 and GPT-5.1 understand images?+
Kimi K2.5 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, Kimi K2.5 or GPT-5.1?+
Neither has a larger sourced maximum output. Kimi K2.5 is — and GPT-5.1 is 128K.
Do Kimi K2.5 and GPT-5.1 support reasoning and tool use?+
Kimi K2.5: 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, Kimi K2.5 or GPT-5.1?+
Kimi K2.5 has 3 sourced provider routes; GPT-5.1 has 2, so Kimi K2.5 has broader tracked availability.
Which offers better value, Kimi K2.5 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.