OpenAI Token Calculator

OpenAI API Pricing (February 2026)

The displayed OpenAI model rates are per one million tokens. Use the calculator to explore cost estimates for a text input.

How to Count OpenAI Tokens

OpenAI uses the tiktoken library for tokenization. Here are the encoding types for each model:

Encoding by Model

• GPT-5, GPT-4o, GPT-4o-mini: cl100k_base encoding
• o3, o3-mini: cl100k_base encoding
• GPT-3.5-turbo: cl100k_base encoding

Python Code Example

import tiktoken

# Example for GPT-4o; choose the exact model tokenizer for other models
enc = tiktoken.encoding_for_model("gpt-4o")
tokens = enc.encode("Your text here")
print(f"Token count: {len(tokens)}")

# Calculate cost
input_tokens = len(tokens)
cost = (input_tokens / 1_000_000) * 2.50  # Source-listed GPT-4o input estimate; verify current provider rate
print(f"Input cost: ${cost:.6f}")

Token Estimation Rules

• 1 token = approximately 4 characters in English
• 1 token = approximately 0.75 words
• 100 words = approximately 133 tokens
• Code typically uses more tokens than natural language

How to Reduce OpenAI API Costs

1. Choose the Right Model

Don't use GPT-5 for everything. Match model capability to task complexity:

• Simple tasks (classification, extraction): GPT-4o-mini ($0.15/1M)
• Standard tasks (chat, generation): GPT-4o ($2.50/1M)
• Complex reasoning: GPT-5 or o3 only when needed

2. Optimize Your Prompts

• Remove unnecessary whitespace and formatting
• Use concise system prompts, they're sent with every request
• Avoid repeating instructions in every message

3. Use Prompt Caching

OpenAI supports automatic caching for eligible repeated prompt prefixes. The cached-input discount depends on the model; GPT-4o has a 50% discount. Repeating a system prompt alone does not guarantee a cache hit: check prefix length, matching, routing and retention requirements. Total costs also include uncached input and output.

4. Batch Requests

Use the Batch API for non-time-sensitive workloads to get 50% discount on all tokens.

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