Vendor-neutral · Pricing updated daily
The reference toolkit for LLM engineers.
Token counting, cost estimation and model comparison — computed in your browser, with no affiliation to any model provider. Nothing you paste is uploaded.
Covers OpenAI, Anthropic, Google, Meta, Mistral and Cohere
Tools
Token Counter
Count tokens for OpenAI, Anthropic and Gemini side by side, with the real tokenizers rather than a character estimate.
OpenLLM Cost Estimator
Project monthly API spend across models from your token volume and request count.
OpenModel Comparison
Context windows, max output and per-million pricing for current models, sortable and filterable.
OpenContext Window Visualizer
SoonSee how much of a model’s context window your prompt actually uses.
Prompt Formatter
SoonTurn a conversation into the exact request shape each provider’s API expects.
JSON Schema Generator
SoonGenerate function-calling schemas for OpenAI, Anthropic and Gemini from one definition.
System Prompt Library
SoonA curated library of system prompts, searchable by category.
Why the numbers differ
llmtools runs the real tokenizers rather than a chars-divided-by-four rule of thumb, because the two disagree badly on anything that is not plain English. The same paragraph of Chinese can differ by nearly half between OpenAI’s two encodings alone. Where a genuine tokenizer is unavailable — Gemini has no public browser implementation — the figure is marked as an estimate rather than dressed up as a count.