Bertrande

Models with the longest context window

Which model handles the longest documents?

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.

How this ranking is built

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.

This is a query, not an opinion. Both figures are shown on every row so you can check the order, and the table sorts on any column if you disagree with our criterion.

Two things to know before trusting this table. Capability scores are published by Artificial Analysis and relayed by the catalogue we read. They are not our measurement, and a score measures the model rather than the seller, so we apply it to every seller of that model. This ranking says nothing about speed or reliability, which we measure only in part: availability is published per upstream host in reliability.json and on the model pages, and we publish no latency at all, for reasons given on the data page. Prices are ours to observe, each carries the date we saw it, and we keep only the cheapest offer per model so that batch and free tiers do not crowd out the answer.

#ModelSellerContext windowtokens40 of 40 heldScale from 512 to 2MInput$ / 1M tokens38 of 40 heldScale from $0.0001 to $600Output$ / 1M tokens38 of 40 heldScale from $0.0001 to $600Contexttokens40 of 40 heldScale from 512 to 2MObserved
1SpaceXAI: Grok 4.20OpenRouter2 000 000$1.25$2.502 000 00018 September 2026
2SpaceXAI: Grok 4.20 Multi-AgentOpenRouter2 000 000$1.25$2.502 000 00018 September 2026
3Auto RouterOpenRouter2 000 000n/an/a2 000 00018 September 2026
4Pareto Code RouterOpenRouter2 000 000n/an/a2 000 00018 September 2026
5DeepSeek: DeepSeek V4 Flash LatestOpenRouter1 310 720$0.055$0.1651 310 72018 September 2026
6DeepSeek: DeepSeek V4 Flash 0731OpenRouter1 310 720$0.060$0.1201 310 72018 September 2026
7Z.ai: GLM Flash LatestOpenRouter1 310 720$0.075$0.2501 310 72017 September 2026
8Z.ai: GLM 5.3 FlashOpenRouter1 310 720$0.090$0.3001 310 72018 September 2026
9Meta: Llama 4 ScoutOpenRouter1 310 720$0.100$0.3001 310 72018 September 2026
10Z.ai: GLM LatestOpenRouter1 310 720$0.900$3.001 310 72018 September 2026
11OpenAI: GPT-5.6 LunaOpenRouter1 050 000$0.200$1.201 050 00018 September 2026
12OpenAI: GPT-5.6 Luna ProOpenRouter1 050 000$0.200$1.201 050 00018 September 2026
13OpenAI: GPT Luna LatestOpenRouter1 050 000$0.200$1.201 050 00018 September 2026
14Xiaomi: MiMo-V2.5-ProOpenRouter1 050 000$0.435$0.8701 050 00018 September 2026
15OpenAI: GPT-5.6 SolOpenRouter1 050 000$2.00$10.001 050 00018 September 2026
16OpenAI: GPT-5.6 Sol ProOpenRouter1 050 000$2.00$10.001 050 00018 September 2026
17OpenAI: GPT-5.6 TerraOpenRouter1 050 000$2.00$12.001 050 00018 September 2026
18OpenAI: GPT-5.6 Terra ProOpenRouter1 050 000$2.00$12.001 050 00018 September 2026
19OpenAI GPT LatestOpenRouter1 050 000$2.00$10.001 050 00010 September 2026
20OpenAI: GPT Sol LatestOpenRouter1 050 000$2.00$10.001 050 00018 September 2026
21OpenAI: GPT Terra LatestOpenRouter1 050 000$2.00$12.001 050 00018 September 2026
22OpenAI: GPT-5.4OpenRouter1 050 000$2.50$15.001 050 00018 September 2026
23OpenAI: GPT-5.5OpenRouter1 050 000$5.00$30.001 050 00018 September 2026
24OpenAI: GPT-6 AstraOpenRouter1 050 000$10.00$50.001 050 00018 September 2026
25OpenAI: GPT-6 Astra ProOpenRouter1 050 000$10.00$50.001 050 00018 September 2026
26OpenAI: GPT Astra LatestOpenRouter1 050 000$10.00$50.001 050 00018 September 2026
27OpenAI: GPT-5.4 ProOpenRouter1 050 000$30.00$1801 050 00018 September 2026
28OpenAI: GPT-5.5 ProOpenRouter1 050 000$30.00$1801 050 00018 September 2026
29Meituan: LongCat 2.0OpenRouter1 048 756$0.300$1.201 048 75618 September 2026
30Google: Lyria 3 Clip PreviewOpenRouter1 048 576$0.000$0.0001 048 57618 September 2026
31Google: Lyria 3 Pro PreviewOpenRouter1 048 576$0.000$0.0001 048 57618 September 2026
32Ox AlphaOpenRouter1 048 576$0.000$0.0001 048 57625 August 2026
33DeepSeek: DeepSeek V4 Flash 0423OpenRouter1 048 576$0.04984$0.099681 048 57618 September 2026
34Poolside: Laguna S 2.1OpenRouter1 048 576$0.090$0.1801 048 57618 September 2026
35Google: Gemini 2.5 Flash LiteOpenRouter1 048 576$0.100$0.4001 048 57618 September 2026
36Meta: Muse Spark 1.2 ContributorOpenRouter1 048 576$0.100$0.2001 048 57618 September 2026
37Meta: Muse Spark 1.3 ContributorOpenRouter1 048 576$0.100$0.2001 048 57618 September 2026
38DeepSeek: DeepSeek Flash LatestOpenRouter1 048 576$0.150$0.6001 048 57618 September 2026
39Meta: Llama 4 MaverickOpenRouter1 048 576$0.1875$0.65251 048 57618 September 2026
40deepseek-ai/DeepSeek-V4.1-FlashDeepInfra1 048 576$0.200$0.6001 048 57618 September 2026

502 models meet this criterion. The table shows the first 40, so 462 ranked below the cut are not listed here; the full catalogue holds them all.

A model missing from this table is missing one of the two figures, not judged. We would rather show a shorter list than fill it with guesses.

Other questions we can answer this way