xAI

Grok 4.20 (Reasoning)

CTX1M

83Quality

Reasoning · Vision · Tools

Input$1.25/M

Output$2.50/M

Reasoning Grok for document-heavy analysis and long-horizon tool use

PaidProprietary824/1044

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xAITextUncommon

Grok 4.20 (Reasoning)

Reasoning Grok for document-heavy analysis and long-horizon tool use

grok-4.20-0309-reasoning

Type: Text
Quality: 83 · Top 17% on the Epoch Capabilities Index
Context window: 1,000,000 tokens
Max output: 30,000 tokens
Input price: $1.25 / 1M tokens
Output price: $2.50 / 1M tokens
Cache read: $0.20 / 1M tokens
Cache write: —
Released: Mar 9, 2026
Knowledge cutoff: —
Takes in: Text, Image, PDF
Puts out: Text
Reasoning: Yes
Tool calling: Yes
Structured output: Yes
File attachments: Yes
Access: Paid
License: Proprietary
Rarity: Uncommon
Set number: 824/1044

Open xAI docs Quality 83 Where to run it 15 Evolution 1/5 Meet its creature Battle Gemini 3.5 Flash Lite

Weights aren’t public. Use is governed by xAI’s terms. Specs from models.dev, last changed Oct 19, 2026. Official source: docs.x.ai.

How good is it?

Public leaderboard scores for Grok 4.20 (Reasoning), refreshed daily from Epoch AI and LMArena.

Top 17% of the 277 models on the Epoch Capabilities Index: #49.

Quality is the share of a leaderboard’s models this one beats, from 0 to 100. Chat models are rated on Epoch AI’s Capabilities Index when it lists them, otherwise on LMArena; image and video models on LMArena’s image and video arenas.

Leaderboards

Epoch Capabilities Index#49 of 277
One number fitted from dozens of hard benchmarks, from science questions to agentic coding.152.1 index
Listed as Grok 4.20

Benchmarks Epoch AI runs

Scores from Epoch AI, licensed CC BY 4.0. Boards list models under their own names, so a close match is shown with the name it was scored under. Credits

Where to run it

15 providers sell Grok 4.20 (Reasoning) through an API. Prices are per million tokens, cheapest first.

CheapestDevPass (LLM Gateway)$1.25 in · $2.50 out
From the labxAI$1.25 in · $2.50 out

API providers

Provider	Input	Output	Context
DevPass (LLM Gateway)Cheapest paid`grok-4-20-reasoning`	$1.25	$2.50	2M
Eden AI`xai/grok-4.20-0309-reasoning`	$1.25	$2.50	1M
Impossibl`xai/grok-4.20-0309-reasoning`	$1.25	$2.50	1M
Kilo Gateway`x-ai/grok-4.20`	$1.25	$2.50	2M
Merge Gateway`xai/grok-4.20-0309-reasoning`	$1.25	$2.50	1M
NanoGPT`x-ai/grok-4.20`	$1.25	$2.50	2M
OCI Generative AI`xai.grok-4.20-reasoning`	$1.25	$2.50	1M
OpenRouter`x-ai/grok-4.20`	$1.25	$2.50	2M
Tempr Gateway`xai/grok-4.20-0309-reasoning`	$1.25	$2.50	1M
Vertex`xai/grok-4.20-reasoning`	$1.25	$2.50	2M

Show 5 more providers

Provider	Input	Output	Context
xAIOfficial`grok-4.20-0309-reasoning`	$1.25	$2.50	1M
Venice AI`grok-4-20`	$1.42	$2.83	2M
Azure`grok-4-20-reasoning`	$2.00	$6.00	262K
Cloudflare AI Gateway`xai/grok-4.20-0309-reasoning`	$2.00	$6.00	2M
Ofox`x-ai/grok-4.20`	$4.00	$12.00	2M

From models.dev and Hugging Face, checked daily. Resellers’ listings can lag behind their price pages, so confirm with the provider before you commit.

Face off

Current text models from other labs at a similar output price.