AI & LLM
Token, cost & context tools for LLMs
Gemini Token Counter — Estimate Tokens for Google Gemini
Google Gemini uses a proprietary SentencePiece tokenizer that is not publicly released. This calculator uses a calibrated estimate of 1 token per 3.8 characters, derived from published benchmarks and Google's own tokenization guidance. For the reference sentence "The quick brown fox jumps over the lazy dog.", Gemini 2.5 Pro is estimated at 12 tokens ≈ 9 words. Gemini 2.5 Pro has a 1,048,576-token context window (≈ 1.0M tokens) at $1.25/M input tokens (≤ 200K prompt). Paste your document or system prompt to estimate whether it fits within Gemini's context.
Sample: "The quick brown fox jumps over the lazy dog."
- Estimated tokens (Gemini, chars ÷ 3.8): 12
- Word equivalent (tokens × 0.75): ≈ 9 words
- Gemini 2.5 Pro context window: 1,048,576 tokens
- Gemini 2.5 Pro max output: 65,536 tokens
- Tokenizer accuracy: ESTIMATED (SentencePiece, proprietary) — as of 2026-07-03
Frequently asked questions
How accurate is the Gemini token estimate?
Google's Gemini tokenizer (SentencePiece) is not publicly distributed. The estimate here (≈1 token per 3.8 characters for English text) aligns with published community benchmarks and Google's own guidance. Accuracy is typically within ±10–15% for standard English text. For multimodal inputs (images, video, audio), tokens are counted differently — image tokens depend on resolution and are not estimated by this text-only tool.
What is the context window of Gemini 2.5 Pro and how does it compare to GPT-5.5?
Gemini 2.5 Pro has a 1,048,576-token context window (≈1,049K tokens). GPT-5.5 has a 1,050,000-token window. Both are roughly 1M-token context models. Gemini 2.5 Pro's max output is 65,536 tokens per response, versus GPT-5.5's 128,000. Input pricing differs: Gemini 2.5 Pro is $1.25/M (≤200K prompt) vs GPT-5.5's $5.00/M.