AI Cost Calculator
OpenAI API Cost Calculator
Estimate OpenAI API costs by model, tokens per call, and monthly volume. Get per-request, monthly, and annual projections instantly.
Fast and affordable for most use cases · $0.40 / 1M input · $1.60 / 1M output
Estimated monthly cost
$12.00
Per API call
$0.0012
Monthly (10,000 calls)
$12.00
Annual (estimated)
$144.00
Input (1,000 tokens × 10,000 calls)$4.00
Output (500 tokens × 10,000 calls)$8.00
Output tokens cost 2.0x more than input tokens for this model. Setting a lower max_tokens limit is the fastest way to reduce your API bill.
GPT-4.1 Nano would cost $0.0003 per call for the same token counts, saving $0.0009 per request.
Model pricing reference
| Model | Input / 1M | Output / 1M |
|---|---|---|
| GPT-4o | $2.50 | $10.00 |
| GPT-4.1 | $2.00 | $8.00 |
| GPT-4.1 Miniselected | $0.40 | $1.60 |
| GPT-4.1 Nano | $0.10 | $0.40 |
| GPT-3.5 Turbo | $0.50 | $1.50 |
Prices are per million tokens. Check openai.com/api/pricing for the latest rates.
Frequently asked questions
How are OpenAI API costs calculated?
OpenAI charges separately for input tokens (text you send) and output tokens (text the model generates), priced per million tokens. If GPT-4.1 Mini costs $0.40 per 1M input tokens and your prompt is 500 tokens, you pay $0.0002 per call. This calculator multiplies those rates by your monthly call volume to project total costs.
Why do output tokens cost more than input tokens?
Output generation requires the model to process each token sequentially in a forward pass. Input tokens are processed in parallel. Sequential computation is significantly more GPU-intensive, which is why all major providers price output tokens at 2–5× the input rate.
What is the difference between GPT-4.1 and GPT-4.1 Mini?
GPT-4.1 is OpenAI's full-capability model for complex reasoning and code. GPT-4.1 Mini costs roughly 80% less per token and handles most everyday tasks, summarization, classification, Q&A, with comparable quality. For most production workloads, Mini is the better starting point.
How can I reduce my OpenAI API bill?
Three levers move the needle most: use a smaller model for simpler tasks, cap output length with max_tokens, and implement prompt caching for repeated system prompts. Moving 50% of calls from GPT-4.1 to Mini alone can cut monthly costs by 40% or more.
How accurate are the cost estimates?
Estimates use OpenAI's published per-token rates. Actual costs may differ if OpenAI adjusts pricing or if you qualify for volume discounts. Token counts use a GPT-compatible tokenizer, accurate to within a few percent. Always verify current rates at platform.openai.com before finalizing budgets.