# Grok 4 ![Organization](https://img.shields.io/badge/Org-xAI-000000) ![Type](https://img.shields.io/badge/Type-Reasoning%20%2B%20tool%20use-555) ![Context](https://img.shields.io/badge/Context-256K%20tokens-1f6feb) ![Pricing](https://img.shields.io/badge/Price-%243%20%2F%20%2415%20per%201M-2da44e) ![License](https://img.shields.io/badge/License-Proprietary-d29922) ![Modality](https://img.shields.io/badge/Modality-Text%20%2B%20Vision-8957e5) ![Released](https://img.shields.io/badge/Released-Jul%202025-555) > **Quick answer:** Grok 4 is xAI's frontier reasoning model, released 9 July 2025. It was trained with large-scale reinforcement learning on xAI's Colossus cluster and ships with native tool use and real-time search across X and the web, plus a 256K-token context window. xAI reports 87.5% on GPQA, 91.7% on AIME 2025, and 38.6% on Humanity's Last Exam (with tools). It is a closed, API-only model. ## At a Glance **Where Grok 4 leads** - Frontier math and science reasoning — 87.5% on GPQA, 91.7% on AIME 2025, 90% on HMMT 2025. - Native, RL-trained tool use with real-time search across X and the web. - Strong long-horizon planning — tops Vending-Bench with $4,694.15 net worth (avg of 5 runs). **Where it lags** - A 256K context window, smaller than the 1M windows of Claude Opus 4.6 and Gemini 3 Pro. - Many headline scores rely on tools or the Grok 4 Heavy variant; closed and API-only with no open weights. **Best for:** tool-driven, search-heavy reasoning and math workloads. ## What Grok 4 Is Grok 4 is xAI's flagship model, built by scaling reinforcement learning to pretraining levels on the 200,000-GPU Colossus cluster. xAI describes it as setting a new state of the art for closed models on reasoning, and a defining feature is native tool use: Grok 4 was trained with RL to drive a code interpreter, browse the web, and run advanced keyword and semantic search across X — choosing its own queries and digging as deep as a research question requires. A more powerful parallel-test-time-compute variant, Grok 4 Heavy, considers multiple hypotheses at once and was the first model to cross 50% on Humanity's Last Exam. Its benchmark profile is heavily weighted toward math, science, and reasoning: 87.5% on GPQA, 91.7% on AIME 2025, 90% on HMMT 2025, and a frontier-leading 15.9% on the deliberately hard ARC-AGI-2. On the agentic Vending-Bench business simulation, xAI reports Grok 4 finishing with $4,694.15 net worth (averaged across five runs), well ahead of other models and human baselines — a long-horizon planning signal. The API exposes a 256K-token context window and multimodal understanding across text and vision. For Benchgen, Grok 4 is an API-benchmarked model with no open weights. xAI's published scores show strong reasoning and search behaviour, but only a verified, repeated-trial run on a real domain task reveals whether that translates into reliable end-to-end completion under a consistent rubric. That reliability-under-repetition view is what Benchgen is built to surface. ## Specifications | Field | Value | |---|---| | Organization | xAI | | Model type | Reasoning model with native tool use and real-time search (Grok 4 Heavy variant) | | API identifier | `grok-4` | | Access | Closed, API only (xAI API, SuperGrok, Premium+) | | Context window | 256K tokens | | License | Proprietary | | Release date | 9 July 2025 | | Knowledge cutoff | November 2024 | | Modality | Multimodal (text and vision) | ## Pricing | | Input (per 1M tokens) | Output (per 1M tokens) | |---|---|---| | xAI | $3.00 | $15.00 | Prompts above 128k tokens are billed at $6.00 / $30.00 per 1M. Source: [xAI API pricing](https://x.ai/api). ## Context Window Grok 4 has a **256K-token context window** — roughly **380 pages** of text in a single request. That is smaller than the 1M-token windows of Claude Opus 4.6 and Gemini 3 Pro, but ample for large documents and multi-file codebases, and it pairs with native tool use and real-time search to pull in fresh context beyond the window. ## Public Benchmark Scores | Benchmark | Score | Source | Date | |---|---|---|---| | [GPQA](/benchmarks/gpqa-diamond) | 87.5% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | [AIME 2025](/benchmarks/aime-2025) | 91.7% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | HMMT 2025 | 90% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | Humanity's Last Exam (w/ Python + Internet) | 38.6% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | USAMO 2025 | 37.5% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | LiveCodeBench (Jan–May) | 79% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | ARC-AGI-2 | 15.9% | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | | Vending-Bench (net worth, avg of 5 runs) | $4,694.15 | [xAI — Grok 4](https://x.ai/news/grok-4) | 2025-07 | *Scores above are reported by xAI and shown for context. They are not Benchgen measurements. Many figures use tools (Python interpreter and internet search), and the Grok 4 Heavy variant posts higher numbers (e.g. 50.7% on Humanity's Last Exam text-only subset, 100% on AIME 2025 with Python). See the source for methodology.* ## Grok 4 vs Alternatives | Model | Context | GPQA | Price (in/out per 1M) | |---|---|---|---| | **Grok 4** | 256K | 87.5% | $3 / $15 | | [GPT-5](/models/openai/gpt-5) | 400K | 88.4% (pro) | $1.25 / $10 | | [Gemini 3 Pro](/models/google/gemini-3-pro) | 1M | 91.9% | $2 / $12 | Grok 4's reasoning is frontier-level and its native tool use plus real-time X/web search are genuine differentiators, but its 256K context window trails rivals' 1M windows and several headline scores depend on tools or the Heavy variant. For a builder, Grok 4 is the pick when search-grounded, tool-driven reasoning matters more than raw context size. *(Rival scores attributed to [OpenAI](https://openai.com/index/introducing-gpt-5/) and [Google](https://blog.google/products/gemini/gemini-3/); not Benchgen measurements.)* ## How Grok 4 Performs on Real Agent Tasks Grok 4's most agent-relevant public result is Vending-Bench: xAI reports it dominating the simulated business with $4,694.15 net worth and 4,569 units sold (averaged over five runs), far ahead of Claude Opus 4 and human baselines. Combined with native, RL-trained tool use — autonomous web and X search, code execution — Grok 4 is clearly built for multi-step, tool-driven workflows rather than single-turn answers. What those benchmarks cannot tell you is how Grok 4 behaves on a *specific* domain workflow, run many times, under a consistent rubric. Vending-Bench measures planning in a synthetic retail sim; what agent builders actually need is reliable, repeated completion of the task in front of them — including how often the model fails, and why. That reliability-under-repetition view is what Benchgen is built to surface, and it is the dimension public benchmarks leave open. ## Use Grok 4 via API ```python from openai import OpenAI # xAI exposes an OpenAI-compatible API client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.x.ai/v1") response = client.chat.completions.create( model="grok-4", messages=[{"role": "user", "content": "Summarize this contract clause..."}], ) print(response.choices[0].message.content) ``` ## Related Models & Benchmarks - Compare: [GPT-5](/models/openai/gpt-5) · [Claude Opus 4.6](/models/anthropic/claude-opus-4-6) · [Gemini 3 Pro](/models/google/gemini-3-pro) · [Claude Sonnet 4.6](/models/anthropic/claude-sonnet-4-6) - Benchmarks: [GPQA Diamond](/benchmarks/gpqa-diamond) · [AIME 2025](/benchmarks/aime-2025) ## Frequently Asked Questions

What is Grok 4?

It is xAI's frontier reasoning model, released 9 July 2025, trained with large-scale reinforcement learning and built around native tool use and real-time search across X and the web.

What is Grok 4's context window?

256,000 tokens — roughly 380 pages of text — via the xAI API.

How much does Grok 4 cost?

$3 per million input tokens and $15 per million output tokens; prompts above 128k tokens are billed at $6 / $30 per million.

How does Grok 4 score on reasoning benchmarks?

xAI reports 87.5% on GPQA, 91.7% on AIME 2025, 90% on HMMT 2025, and 15.9% on ARC-AGI-2. The Grok 4 Heavy variant scores higher, including 50.7% on the Humanity's Last Exam text-only subset.

Is Grok 4 open source?

No. It is a proprietary, closed model available only through xAI's API and Grok subscriptions; there are no downloadable weights.

--- *Specs and scores sourced from [xAI's Grok 4 announcement](https://x.ai/news/grok-4). Third-party benchmark scores attributed inline to xAI. Benchgen scores, where shown, are produced on Benchgen infrastructure. Last updated 2026-06-17.*

Grok 4 — Files