OpenAI API Cost Calculator — Estimate GPT Model Spend
Use this free OpenAI API Cost Calculator to estimate how much your usage of GPT models — including GPT-4o, GPT-4o Mini, GPT-3.5 Turbo, and other supported models — will cost before you make API calls. Simply enter your expected input tokens, output tokens, and number of requests to see your estimated cost per request and for larger usage volumes. This helps developers, startups, and product teams plan their AI budgets, compare pricing across models, and avoid unexpected billing surprises when integrating with OpenAI’s API.
Understanding OpenAI API Pricing
OpenAI charges based on the number of tokens processed. Each model has different pricing for input (prompt) tokens and output (completion) tokens. Newer models like GPT-4o offer better performance at competitive pricing.
Calculate Your OpenAI Costs
Example: Customer Support Chatbot
Scenario: A customer support chatbot handling 1,000 conversations per day
- Model: GPT-4o Mini
- Average input: 150 tokens (context + question)
- Average output: 200 tokens (response)
- Cost per conversation: ~$0.00015
- Daily cost: ~$0.15
- Monthly cost: ~$4.50
Frequently Asked Questions
How are OpenAI API costs calculated?
OpenAI charges separately for input tokens (your prompt) and output tokens (the model's response). Each model has different per-token pricing. The total cost is: (input_tokens × input_price + output_tokens × output_price) / 1000.
Which OpenAI model should I choose?
GPT-4o Mini is ideal for most use cases - it's fast, affordable, and highly capable. Use GPT-4o for complex reasoning tasks. GPT-3.5 Turbo is good for simple, high-volume applications where cost is the primary concern.
How can I reduce OpenAI API costs?
Optimize your prompts to use fewer tokens, implement response caching for common queries, set appropriate max_tokens limits, and choose the smallest model that meets your quality requirements.