Token Counter with Tiktoken

import tiktoken

def count_tokens(text: str, model: str = "gpt-4o") -> int:
    """Count tokens for a given text and model."""
    enc = tiktoken.encoding_for_model(model)
    return len(enc.encode(text))

def estimate_cost(
    prompt_tokens: int,
    completion_tokens: int,
    model: str = "gpt-4o",
) -> float:
    """Estimate API cost in USD."""
    pricing = {
        "gpt-4o": {"input": 2.50, "output": 10.00},
        "gpt-4o-mini": {"input": 0.15, "output": 0.60},
    }
    rates = pricing.get(model, pricing["gpt-4o"])
    input_cost = (prompt_tokens / 1_000_000) * rates["input"]
    output_cost = (completion_tokens / 1_000_000) * rates["output"]
    return round(input_cost + output_cost, 6)

# Usage:
# tokens = count_tokens("Hello, how are you?")
# cost = estimate_cost(prompt_tokens=500, completion_tokens=200)