Gemini Token Counter -- Pro & Flash Models

Gemini Token Counter

Gemini Token Counter estimates how many tokens your text will use with Gemini 3 Pro, Gemini 2.5 Pro, Gemini 2.5 Flash, and other Google AI models. Gemini uses SentencePiece tokenization with a 256K vocabulary (~4.2 characters per token for English).

Gemini Model Comparison

Gemini Pro models have tiered pricing: standard rate for prompts up to 200K tokens, premium rate for longer prompts. Flash models have flat pricing.

*Pro models show standard / long-context pricing. Premium rate applies for prompts over 200K tokens.

How Gemini Tokenization Works

Gemini uses SentencePiece with a Unigram language model for tokenization. Unlike BPE (used by OpenAI and Anthropic), the Unigram model considers all possible segmentations and picks the most probable one.

Key Features of Gemini's Tokenizer

• 256K vocabulary: Larger than OpenAI's 200K, allowing slightly more efficient tokenization
• Multilingual optimization: Excellent support for non-English languages, including CJK
• ~4.2 chars/token: Slightly more efficient than OpenAI (~4.0) for English text
• CountTokens API: Free endpoint to get exact token counts before making API calls

Gemini's Massive Context Windows

Gemini offers the largest context windows commercially available. Gemini 3 Pro Preview and 2.5 Pro support 2 million tokens -- enough for roughly 1.5 million words or 3,000 pages of text. This dwarfs GPT-5's 400K and Claude's 200K standard windows.

However, long-context usage comes with tiered pricing for Pro models. Prompts exceeding 200K tokens are charged at approximately 2x the standard rate. Flash models maintain flat pricing regardless of prompt length.

Frequently Asked Questions

How many tokens does Gemini support?

Gemini has the largest context windows available. Gemini 3 Pro Preview and 2.5 Pro support up to 2 million tokens. Gemini 2.5 Flash and 2.0 Flash support up to 1 million tokens. This is significantly more than GPT-5 (400K) or Claude (200K standard).

What tokenizer does Gemini use?

Gemini uses SentencePiece with a Unigram model and a vocabulary of approximately 256,000 tokens. This is larger than OpenAI's 200K vocabulary, making Gemini slightly more efficient at about 4.2 characters per token for English text.

How much does Gemini cost per token?

Gemini 2.5 Pro costs $1.25 per million input tokens (standard) and $10.00 per million output tokens. Gemini 2.5 Flash is much cheaper at $0.15/1M input. Pro models have tiered pricing with higher rates for prompts over 200K tokens.

What is the Gemini context window?

Gemini 3 Pro Preview and 2.5 Pro have 2 million token context windows -- the largest commercially available. Flash models support 1 million tokens. These far exceed GPT-5's 400K and Claude's 200K standard windows.

How does Gemini pricing work for long documents?

Gemini Pro models use tiered pricing. For prompts up to 200K tokens, standard rates apply ($1.25/1M for 2.5 Pro). For prompts over 200K tokens, a premium rate kicks in ($2.50/1M for 2.5 Pro). Flash models have flat pricing regardless of length.

Is there a free tier for Gemini?

Yes. Google offers a free tier for the Gemini API through Google AI Studio with rate limits. The free tier includes access to Gemini 2.5 Flash and other models with limited requests per minute and per day. Paid usage requires a Google Cloud billing account.

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