OpenAI Cost Calculator
Estimate OpenAI GPT-5 API spend per call, day, month and year — then compare against Claude and Gemini and see how much switching could save.
Inputs
Choose the model tier you plan to use in production.
Average prompt size per API call. A page of text ≈ 750 tokens.
Average completion length. Short answers ≈ 200–500 tokens.
Total API calls per month across all users / jobs.
Fraction of input tokens served from prompt cache (costs ~10× less). 0 = no caching.
Cost breakdown
| Item | Monthly | Yearly |
|---|---|---|
| Input tokens | $10,000.00 | $120,000.00 |
| Output tokens | $5,000.00 | $60,000.00 |
| Spend | $62,500.00 | $750,000.00 |
Comparison
| Option | Monthly | Yearly |
|---|---|---|
| OpenAI GPT-5currentcheapest | $62,500.00 | $750,000.00 |
| Claude Claude Sonnet 4.6 | $105,000.00 | $1,260,000.00 |
| Gemini Gemini 2.5 Pro | $62,500.00 | $750,000.00 |
Data updated 2026-06-30 · openai.com/api/pricing openai.com/api/pricing · platform.claude.com/docs/about-claude/pricing platform.claude.com/docs/about-claude/pricing · ai.google.dev/gemini-api/docs/pricing ai.google.dev/gemini-api/docs/pricing
Industry Benchmark
Data updated 2026-06-30 · openai.com/api/pricing openai.com/api/pricing · platform.claude.com/docs/about-claude/pricing platform.claude.com/docs/about-claude/pricing · ai.google.dev/gemini-api/docs/pricing ai.google.dev/gemini-api/docs/pricing
Trends & comparison
Trend
Comparison (monthly vs. yearly)
How to use this calculator
Enter average input/output tokens per request, monthly request volume and optional cache hit ratio. Toggle the Batch API discount for async workloads. Results update instantly with per-call, daily, monthly and yearly cost plus a Claude and Gemini comparison.
Worked example
A RAG chatbot sending 1,000,000 input and 500,000 output tokens across 10,000 requests/month on GPT-5 gets an instant projection and a flag for the cheapest provider plus the annual saving from switching.
Pricing benchmarks
Prices are injected from a versioned JSON config and validated at build time. GPT-5, GPT-5 Mini and GPT-5 Nano bill per million tokens with discounted cached-input pricing and an optional batch discount.
Frequently asked questions
How is OpenAI API cost calculated?▾
Cost = (input tokens ÷ 1,000,000 × input price) + (output tokens ÷ 1,000,000 × output price), times your monthly requests. Cached input tokens bill at a lower rate and the optional Batch API discount applies on top.
What does the cache hit ratio do?▾
It is the share of input tokens served from prompt cache, which is billed at the cheaper cached-input rate. Reusing long system prompts and shared context raises it and lowers effective input cost.
How accurate are the Claude and Gemini comparisons?▾
Comparisons use comparable-tier pricing sourced directly from official provider documentation. Verify against each provider's official price page; the footer shows the data version and source.