Choose a tokenizer by model family
Open the tokenizer that matches your model family. Count tokens, inspect boundaries, and view token IDs when the selected tokenizer exposes them.
OpenAI Tokenizer
Count plain-text tokens with current or legacy OpenAI encodings, then inspect each token boundary and ID in your browser.
Open tokenizer Runs locallyGemini Tokenizer
Count Gemini-compatible plain-text tokens and inspect token boundaries and IDs in your browser.
Open tokenizer Official API countClaude Token Counter
Count the API input tokens for a Claude user message with Anthropic's official token-count endpoint.
Open tokenizer Runs locallyLlama Tokenizer
See how a Llama 3 tokenizer splits plain text, inspect token IDs, and keep your text in the browser.
Open tokenizer Runs locallyGemma Tokenizer
See how Gemma 3 splits plain text into tokens, inspect token IDs, and keep the text in your browser.
Open tokenizer Runs locallyQwen Tokenizer
Tokenize text with the pinned Qwen 3.5 tokenizer, inspect token boundaries and IDs, and keep your input local.
Open tokenizer Runs locallyMistral Tokenizer
Paste text, a prompt, or code to count tokens with the pinned Mistral Medium 3.5 tokenizer, then inspect the exact token pieces and IDs in your browser.
Open tokenizer Runs locallyDeepSeek Tokenizer
Count tokens with the pinned DeepSeek V4 Pro tokenizer and inspect the token pieces and IDs without uploading your text.
Open tokenizerOnline tokenizer questions
Which online tokenizer should I choose?
Choose the model family that will process the text. Token boundaries and IDs are specific to a tokenizer, so the same text can have a different count in another family.
Do these tokenizers upload my text?
OpenAI, Gemini, Llama, Gemma, Qwen, Mistral, and DeepSeek tokenization runs locally in your browser. Claude uses Anthropic's official token-count API and sends the submitted text to Anthropic for counting; StackLens does not store it.
Will a plain-text tokenizer match an API bill exactly?
Not always. Roles, chat templates, tool definitions, images, and provider-specific request formatting can add tokens beyond the plain text entered into a tokenizer.