How this calculator works
Paste your text or enter a word count. The calculator estimates tokens two ways, from the word count and from the number of characters, and uses the larger figure so it errs on the side of caution.
It compares that estimate with common context window sizes and shows the percentage used and how many pages would fit.
The model’s reply also takes up space in the same window, so you can reserve a share for the answer.
Token counts vary between models, because each splits text differently. Treat the results as estimates and leave some headroom.
Worked example
A 50,000-word report
- 50,000 words × 1.33 = about 66,500 tokens.
- With 10% kept free for the reply, a 128K window has about 115,200 usable tokens, so the report uses about 58%.
- At 500 words per page, the report is about 100 pages.
Questions people ask
How many words is 1,000 tokens?
About 750 words of typical English. Code, numbers and many other languages use more tokens per word.
What happens if my text is bigger than the context window?
Depending on the tool, it may refuse the input, cut off part of it, or quietly drop earlier parts of the conversation. Splitting the document into sections or summarising parts first helps.
Is a bigger context window always better?
Not always. Models can pay less attention to details buried in very long inputs. Giving only the relevant sections often produces better answers than pasting everything.
Why does the same text use more tokens in some models?
Each model family uses its own tokenizer, which breaks text into pieces differently. The same paragraph can produce noticeably different token counts.
Last reviewed October 1, 2026