Calculate how much text fits in different context windows.
The LLM Context Window Calculator estimates how many tokens a block of text contains and shows what percentage of each model's context window it fills, with a clear fit or no-fit result. Paste a document and it estimates tokens at roughly four characters per token, then compares against windows ranging from 8K to over 1M. It is aimed at developers and writers checking whether a prompt, transcript or document fits before sending it. Token counts are estimates; exact values depend on the tokenizer.
The calculator divides the character count by four, a common rule of thumb for English. Code, Arabic, emoji and other scripts often use more tokens per character, so the real count can be higher.
Most APIs reject the request or silently truncate it. Truncation can drop instructions or retrieved evidence, so chunk the content or choose a model with a larger window.
Yes. The context window is shared by input and generated output. A long prompt leaves less room for the answer, so reserve space for the expected response before sending.
Canonical pricing and plans: plugsky.com/#sec-pricing · Terms · SLA · Docs