GPT-5.1 token counter
Type or paste a prompt to count GPT-5.1 tokens and estimate what it costs to run — free, live, and private.
Try:
Counts include each model's own chat-template overhead.
128 charsGPT-5.1
OpenAI · 400k context…tokens
About GPT-5.1 tokenization
- Vendor
- OpenAI
- Context window
- 400k tokens
- Pricing (per 1M tokens)
- $1.25 input · $10 output (as of 2026-07-07)
- How we count
- the o200k_base encoding, running entirely in your browser
FAQ
How accurate is this GPT-5.1 token count?
Exact — it uses the o200k_base encoding, running entirely in your browser, the same tokenizer the model uses in production.
Does my prompt leave the browser?
No. Tokenization runs entirely in your browser.
What does a GPT-5.1 request cost?
Input tokens × $1.25/1M plus output tokens × $10/1M (standard tier, as of 2026-07-07). The calculator above does this for your actual prompt.