Token pricing is the foundational billing model for virtually every large language model API on the market today. Understanding how token pricing works is essential for anyone building AI-powered applications, as it directly determines your operational costs and influences architectural decisions.
What Are Tokens?
Tokens are the basic units that language models use to process text. A token roughly corresponds to 3-4 characters in English, or about 75% of a word. For example, the word "hamburger" might be split into "ham," "bur," and "ger" — three tokens. Common words like "the" or "and" are typically single tokens.
Different model providers use different tokenization schemes:
These differences mean the same text can result in slightly different token counts across providers.
How Token Pricing Works
LLM APIs charge separately for:
Input Tokens (Prompt Tokens)
These are the tokens in your request — the system prompt, user message, conversation history, function definitions, and any context you provide. Input tokens are typically cheaper than output tokens because the model processes them in parallel.
Output Tokens (Completion Tokens)
These are the tokens the model generates in response. Output tokens cost more because they're generated sequentially, requiring more compute per token. The ratio between input and output pricing varies by provider but is typically 1:3 to 1:5.
Cached Tokens
Some providers offer discounted pricing for cached input tokens — portions of your prompt that are identical to recent requests. This can reduce input costs by 50-90%.
Current Token Pricing Landscape (2025-2026)
| Model | Input (per 1M tokens) | Output (per 1M tokens) |
|---|---|---|
| GPT-4o | $2.50 | $10.00 |
| GPT-4o-mini | $0.15 | $0.60 |
| Claude 3.5 Sonnet | $3.00 | $15.00 |
| Claude 3.5 Haiku | $0.80 | $4.00 |
| Gemini 1.5 Pro | $1.25 | $5.00 |
| Llama 3.1 70B (via API) | $0.50-0.90 | $0.50-0.90 |
Why Token Pricing Matters for AI Applications
Token pricing has profound implications for application design:
Optimizing for Token Pricing
Smart teams optimize their token usage through several strategies:
The Future of Token Pricing
Token prices have been dropping rapidly — roughly 10x every 18 months. However, usage is growing even faster as AI agents consume far more tokens than simple chatbots. The net effect is that total AI spending continues to rise even as per-token costs fall.