# Models with the longest context window

As of 18 September 2026, the model ranking first for this question is SpaceXAI: Grok 4.20 on OpenRouter, with context window 2 000 000 and an output price of $2.50 per million tokens. Ranked by largest published context window, then lowest input price, across 502 models for which we hold both figures. This ranking ignores speed and reliability: it is a query on price and a relayed capability score, not a verdict on which model serves you best.

Criterion: largest published context window, then lowest input price.
Context length is published by the provider, not measured by us. A long window says what the model accepts, not how well it uses it.

502 models meet this criterion; 40 are listed below.
Scores come from Artificial Analysis, relayed by the catalogue we read, and are not our own measurement. Prices are ours, each carrying the day we observed it. Full provenance per value: https://bertrande.com/en/best/long-context/answer.json

| # | Model | Seller | Context window | Output $/1M | Observed |
|---|---|---|---|---|---|
| 1 | SpaceXAI: Grok 4.20 | OpenRouter | 2 000 000 | $2.50 | 2026-09-18T04:16:25Z |
| 2 | SpaceXAI: Grok 4.20 Multi-Agent | OpenRouter | 2 000 000 | $2.50 | 2026-09-18T04:16:25Z |
| 3 | Auto Router | OpenRouter | 2 000 000 | n/a | 2026-09-18T04:16:25Z |
| 4 | Pareto Code Router | OpenRouter | 2 000 000 | n/a | 2026-09-18T04:16:25Z |
| 5 | DeepSeek: DeepSeek V4 Flash Latest | OpenRouter | 1 310 720 | $0.165 | 2026-09-18T16:15:59Z |
| 6 | DeepSeek: DeepSeek V4 Flash 0731 | OpenRouter | 1 310 720 | $0.120 | 2026-09-18T04:16:25Z |
| 7 | Z.ai: GLM Flash Latest | OpenRouter | 1 310 720 | $0.250 | 2026-09-17T10:12:18Z |
| 8 | Z.ai: GLM 5.3 Flash | OpenRouter | 1 310 720 | $0.300 | 2026-09-18T04:16:25Z |
| 9 | Meta: Llama 4 Scout | OpenRouter | 1 310 720 | $0.300 | 2026-09-18T04:16:25Z |
| 10 | Z.ai: GLM Latest | OpenRouter | 1 310 720 | $3.00 | 2026-09-18T16:15:59Z |
| 11 | OpenAI: GPT-5.6 Luna | OpenRouter | 1 050 000 | $1.20 | 2026-09-18T04:16:25Z |
| 12 | OpenAI: GPT-5.6 Luna Pro | OpenRouter | 1 050 000 | $1.20 | 2026-09-18T04:16:25Z |
| 13 | OpenAI: GPT Luna Latest | OpenRouter | 1 050 000 | $1.20 | 2026-09-18T16:15:59Z |
| 14 | Xiaomi: MiMo-V2.5-Pro | OpenRouter | 1 050 000 | $0.870 | 2026-09-18T04:16:25Z |
| 15 | OpenAI: GPT-5.6 Sol | OpenRouter | 1 050 000 | $10.00 | 2026-09-18T04:16:25Z |
| 16 | OpenAI: GPT-5.6 Sol Pro | OpenRouter | 1 050 000 | $10.00 | 2026-09-18T04:16:25Z |
| 17 | OpenAI: GPT-5.6 Terra | OpenRouter | 1 050 000 | $12.00 | 2026-09-18T04:16:25Z |
| 18 | OpenAI: GPT-5.6 Terra Pro | OpenRouter | 1 050 000 | $12.00 | 2026-09-18T04:16:25Z |
| 19 | OpenAI GPT Latest | OpenRouter | 1 050 000 | $10.00 | 2026-09-10T22:13:01Z |
| 20 | OpenAI: GPT Sol Latest | OpenRouter | 1 050 000 | $10.00 | 2026-09-18T16:15:59Z |
| 21 | OpenAI: GPT Terra Latest | OpenRouter | 1 050 000 | $12.00 | 2026-09-18T16:15:59Z |
| 22 | OpenAI: GPT-5.4 | OpenRouter | 1 050 000 | $15.00 | 2026-09-18T04:16:25Z |
| 23 | OpenAI: GPT-5.5 | OpenRouter | 1 050 000 | $30.00 | 2026-09-18T04:16:25Z |
| 24 | OpenAI: GPT-6 Astra | OpenRouter | 1 050 000 | $50.00 | 2026-09-18T02:27:40Z |
| 25 | OpenAI: GPT-6 Astra Pro | OpenRouter | 1 050 000 | $50.00 | 2026-09-18T02:27:40Z |
| 26 | OpenAI: GPT Astra Latest | OpenRouter | 1 050 000 | $50.00 | 2026-09-18T16:15:59Z |
| 27 | OpenAI: GPT-5.4 Pro | OpenRouter | 1 050 000 | $180 | 2026-09-18T04:16:25Z |
| 28 | OpenAI: GPT-5.5 Pro | OpenRouter | 1 050 000 | $180 | 2026-09-18T04:16:25Z |
| 29 | Meituan: LongCat 2.0 | OpenRouter | 1 048 756 | $1.20 | 2026-09-18T04:16:25Z |
| 30 | Google: Lyria 3 Clip Preview | OpenRouter | 1 048 576 | $0.000 | 2026-09-18T04:16:25Z |
| 31 | Google: Lyria 3 Pro Preview | OpenRouter | 1 048 576 | $0.000 | 2026-09-18T04:16:25Z |
| 32 | Ox Alpha | OpenRouter | 1 048 576 | $0.000 | 2026-08-25T13:24:55Z |
| 33 | DeepSeek: DeepSeek V4 Flash 0423 | OpenRouter | 1 048 576 | $0.09968 | 2026-09-18T16:15:59Z |
| 34 | Poolside: Laguna S 2.1 | OpenRouter | 1 048 576 | $0.180 | 2026-09-18T04:16:25Z |
| 35 | Google: Gemini 2.5 Flash Lite | OpenRouter | 1 048 576 | $0.400 | 2026-09-18T04:16:25Z |
| 36 | Meta: Muse Spark 1.2 Contributor | OpenRouter | 1 048 576 | $0.200 | 2026-09-18T04:16:25Z |
| 37 | Meta: Muse Spark 1.3 Contributor | OpenRouter | 1 048 576 | $0.200 | 2026-09-18T02:27:40Z |
| 38 | DeepSeek: DeepSeek Flash Latest | OpenRouter | 1 048 576 | $0.600 | 2026-09-18T16:15:59Z |
| 39 | Meta: Llama 4 Maverick | OpenRouter | 1 048 576 | $0.6525 | 2026-09-18T04:16:25Z |
| 40 | deepseek-ai/DeepSeek-V4.1-Flash | DeepInfra | 1 048 576 | $0.600 | 2026-09-18T04:10:06Z |

Source: https://bertrande.com/en/best/long-context/
License: CC-BY-4.0, reuse with attribution.