ToyTools Guide
What Is a Context Window?
A context window is a published token capacity. This page estimates it as characters divided by 4. Runs entirely on your device. Nothing is uploaded.
Quick Answer
What is a context window? It is the published token capacity of one model. This context window checker estimates a prompt length as a token estimate: characters per token is 4, and that divisor is ours. Why is characters divided by 4 only an estimate? A tokenizer can split the same text differently. The percent is not an official token count.
Open Context Fit Checker →Why it matters
For example, a draft that looks short in words can still be long in characters. The estimate is a warning before you paste, not a bill and not a recommendation.
How it works
How to estimate whether a prompt fits: paste the text and pick a model. How to read the source note on a model row: it is the vendor page and the date it was read. An estimate vs an official tokenizer is that gap. Character count vs token count is two different numbers on the same page. The page does not recommend a model.
Common Mistakes
Related Tools
You May Also Need
You may also need
- Character CounterSee the character count the estimate starts from
- Prompt PackerAssemble the draft this estimate is about
- Word CounterCount words in the same draft