Home / Grok context window: size by model and how to check yours
Grok context window: size by model and how to check yours
Grok models advertise some of the largest context windows around, but what you get in the app can differ from the model figure, and a very long chat still degrades. Here are the reported numbers, the caveats, and a way to check your own chat.
Grok context window size by model
Third-party summaries, reviewed 2026-10-08, report these figures. They come from aggregators rather than xAI's own pages, and some disagree.
| Model | Reported context window |
|---|---|
| Grok 4 | About 256K tokens |
| Grok 4 Fast | About 2M tokens |
| Newer Grok models | Reported between 1M and 2M tokens |
Model and API limits are not the same as what the Grok app gives you. For other assistants see context window sizes: ChatGPT vs Claude vs Gemini.
What happens when a Grok chat gets too long
As with any assistant, the conversation is resent with each message. Long chats drift: forgotten instructions, repeated mistakes and contradictions show up before any hard cutoff. See what context rot is.
How to check how full your Grok chat is
Grok does not show a running meter. Paste the conversation into the free token counter to estimate its size. ContextMeter does not support Grok yet; it works on ChatGPT and Claude today.
What to do when it is nearly full
- Finish the current topic.
- Ask Grok for a structured summary with the handoff prompt.
- Start a new chat and paste the summary in.
Frequently asked questions
How big is Grok's context window?
It depends on the model. Third-party summaries report about 256K tokens for Grok 4 and about 2M for Grok 4 Fast, with newer models listed between 1M and 2M. Limits in the Grok app on grok.com or X may be lower than model figures, so check xAI's own documentation.
Does Grok show how full the context window is?
Not in the normal chat. There is no running counter, so you only notice when answers get worse or the chat stops accepting input.
Does ContextMeter work on Grok?
Not yet. It works on ChatGPT and Claude today. The free token counter on this site estimates the size of any text you paste, which is a way to check a long Grok chat.
What should I do when a Grok chat gets too long?
Finish the topic, ask for a structured summary with the handoff prompt, and start a new chat with that summary pasted in.
Last reviewed 2026-10-08. Numbers change often; see the sources linked on this page.
ContextMeter is a free, private browser extension that shows how full your ChatGPT or Claude chat is while you use it, and helps you carry the chat into a fresh one. See how it works.