Recommended tools
How this calculator works
The calculator models two pricing approaches side by side. For pay-as-you-go (PAYG), total cost is computed by dividing your total monthly tokens by one million and multiplying by the provider's per-million-token price. For subscription plans, the cost equals the flat monthly fee plus any overage charges — overage is calculated by taking any call volume exceeding the plan's included calls and multiplying by the provider's overage rate per call. The two totals are compared directly to identify the break-even point where one model becomes cheaper than the other at your usage volume.
Example monthly API bills by workload
Illustrative monthly bills for three common workload profiles, computed from the official standard-tier prices (input tokens × input price + output tokens × output price). Match your own usage pattern to a row, then model it in the calculator above.
| Workload profile | Monthly volume | Model | Estimated bill |
|---|---|---|---|
| Light — personal assistant or autocomplete | 2M input + 0.5M output | GPT-5 mini | ~$1.50 |
| Light — same volume on a frontier model | 2M input + 0.5M output | GPT-5.1 | ~$7.50 |
| Medium — RAG support bot on a budget model | 30M input + 6M output | Gemini 2.5 Flash-Lite | ~$5.40 |
| Medium — same volume on a fast tier | 30M input + 6M output | Claude Haiku 4.5 | ~$60 |
| Medium — same volume on a workhorse tier | 30M input + 6M output | Claude Sonnet 4.5 | ~$180 |
| Heavy — document or content batch pipeline | 100M input + 40M output | GPT-5.1 | ~$525 |
| Heavy — same volume via batch API (−50%) | 100M input + 40M output | GPT-5.1 (batch) | ~$263 |
Useful scenarios
- A solo developer building an AI feature — estimating whether a $20/month ChatGPT API plan covers 50K calls/month or if PAYG is cheaper.
- A freelancer comparing OpenAI API usage at 200K calls/month vs a $100/month enterprise plan with included calls.
- A creator using an image generation API — comparing subscription vs PAYG for 10K generations/month at 4,000 tokens each.
FAQ
When does a subscription plan make sense?
A subscription plan is usually cheaper when you use enough to hit the included calls. If your monthly call volume is within 60-80% of the included amount, you're getting good value. Below that, PAYG may be cheaper.
How do I estimate tokens per call accurately?
Look at your actual usage data if available. If you're planning a new project, estimate based on: simple queries = 500-1K tokens, analysis tasks = 2-4K tokens, document processing = 8-15K tokens. Always add 20% buffer to your estimate.
Should I use multiple API providers?
It depends. Using multiple providers gives you flexibility and backup, but adds complexity. Some providers offer better pricing for specific tasks (e.g., Anthropic for long documents, OpenAI for general chat). Compare per-token costs across providers using the Token Cost Calculator.