AI Model Comparison
Grok vs ChatGPT
xAI's Grok against the models behind ChatGPT: context windows up to 2 million tokens, reasoning you can switch off, and where OpenAI's lineup keeps the edge.
What to know before comparing Grok and ChatGPT
Grok is both xAI's consumer assistant inside X and a model family you can call directly. ChatGPT is OpenAI's app, with the GPT-5 family underneath. The consumer products differ mostly in personality and distribution, the model families differ in measurable ways, and this page covers both.
In order: what the apps cost, then the model families tier by tier with live pricing and context windows, a practical read on which lineup fits which work, and head-to-head pages with full specs and privacy detail.
What the apps cost
Grok's access is tangled up with X's subscriptions, ChatGPT's is a straight freemium ladder. Prices checked August 2026; the links below carry the makers' current numbers.
Grok
xAI
ChatGPT
OpenAIGrok and GPT-5 are models you can use outside the apps
Each app is powered by a family of AI models, Grok by xAI's Grok models and ChatGPT by the GPT-5 family, and those models can be used directly by any software through an API, with no X account or ChatGPT subscription involved.
Unlike the apps, the models are metered per million tokens (a token is a short chunk of text, roughly three quarters of a word). That is what the board below compares, tier by tier, which is the choice you actually make when you build.
The lineups, side by side
Live specs and per-million-token prices, straight from the providers. Where several providers serve a model, the lowest price is shown.
Grok
xAIxAI ships at an unusually fast cadence. Grok 4.6 currently tops the line, Grok 4.5 before it sharpened the family's focus on software engineering with reasoning you can switch on or off per request, and the Grok 4.1 Fast line pairs a 2 million token context window with high-throughput inference.
GPT, the models behind ChatGPT
OpenAIOpenAI's lineup runs from the frontier GPT-5.6 Sol through the balanced Terra and high-volume Luna, with GPT-5.3 Codex as the dedicated agentic coding model and an open-weight release in GPT-OSS 120B.
Where Grok wins
Grok's standout numbers are context and control. Grok 4.1 Fast Reasoning pairs extended chain-of-thought with a 2 million token context window, the largest of any family on this page, which fits an entire codebase, a discovery file or days of logs in a single request. Grok 4.5 aimed the line squarely at software engineering and multi-step agent work, with a 500K window and reasoning that can be toggled per request, so you pay for thinking only on the calls that need it, and Grok 4.6 now tops the family.
The cadence itself is an advantage: xAI revs its flagship at an unusually short interval, and teams that ride the newest capability tier get the gains early.
Where the GPT lineup wins
The GPT lineup's advantage is depth and breadth: GPT-5.6 Sol leads long-horizon agentic evaluations across terminal work, browsing and computer use, GPT-5.3 Codex holds state-of-the-art results on SWE-Bench Pro and Terminal-Bench, and the lineup offers clean price steps, from the frontier down to Luna for classification and extraction at minimal cost. OpenAI also publishes the open-weight GPT-OSS 120B, which xAI has no current equivalent for.
What about pricing?
The board above shows the providers' own per-million-token prices live, so nothing here goes stale. Grok's switchable reasoning is the lever to know about: the same model can run cheap and fast on routine calls and spend thinking tokens only when a task earns it. On the GPT side the equivalent lever is tier routing, dropping from Sol to Terra or Luna when the task allows, plus Codex's unusually low output-token appetite on coding work.
How to choose
Reach for Grok when raw context length or per-request reasoning control decides the problem: whole-repo analysis, giant document sets, high-throughput reasoning pipelines. Reach for the GPT lineup when the work is long-horizon agents, computer use or the hardest agentic coding. Both are one model-name change apart on Opper, so the decisive evidence is your own evaluation set, not anyone's launch post.
The LLM leaderboard tracks current benchmark standings, and the head-to-head pages below carry full specs, pricing and privacy posture per model.
Compare the models head-to-head
Full side-by-side specs, pricing, privacy and benchmarks for the pairings people actually weigh.
Or build your own on the interactive compare page, up to four models at a time.
Common questions
Is Grok better than ChatGPT?
As apps they are hard to compare, Grok lives inside X while ChatGPT is a standalone product. As model families, Grok competes at the frontier with standout context length and switchable reasoning, while the GPT lineup is broader and leads the big agentic benchmarks. The LLM leaderboard shows where the current versions land.
What is special about Grok's context window?
The Grok 4.1 Fast line works across 2 million tokens, roughly double the 1M windows that current Claude, Gemini and GPT flagships offer. That is the difference between chunking a large codebase or document archive and simply sending it whole.
Do I need an X subscription to use Grok?
Not for the models. The consumer Grok assistant is tied to X's product tiers, but the Grok models are available directly by API, including through Opper, where they share one API key with every other family on this page and no X account is involved.
Can I run Grok and GPT models side by side?
Yes. Opper exposes both behind one OpenAI-compatible endpoint with EU hosting and zero data retention by default, so A/B tests and per-task routing are configuration rather than code. Start from the models directory or the interactive compare page.