AI Cost Calculator
Estimate your monthly OpenAI, Anthropic, or Google Gemini API spend based on model, token usage, and request volume. Free, no sign-up required.
Prices sourced from OpenAI, Anthropic, and Google official pricing pages · Last updated: March 2026
Your usage
Multimodal GPT-4 model
Total API calls across all users per day
Typical range: 200–2,000. 1 token ≈ 0.75 words.
Typical range: 100–1,000. Output costs are usually 3–5× input.
Estimated cost
Monthly estimate
$187.50
$6.25/day · $0.0063/request
Cost breakdown
Monthly requests
30,000
Total monthly tokens
30,000,000
Input price
$2.5/M tokens
Output price
$10/M tokens
This is an estimate based on standard pricing. Actual costs may vary with prompt caching, batch API discounts, or volume commitments. Prices are updated periodically — verify against your provider's dashboard.
This shows your total. PerUnit shows you which customers are driving it.
Break down your AI spend by customer, feature, and pricing tier — so you know who to charge more, what to gate, and where to cut.
Get early access to PerUnitFrequently asked questions
- How does OpenAI charge for API usage?
- OpenAI charges based on the number of tokens processed — both input tokens (your prompt) and output tokens (the model's response). Prices vary by model and are quoted per 1 million tokens. For example, GPT-4o costs $2.50 per 1M input tokens and $10.00 per 1M output tokens as of March 2026.
- What is a token in AI models?
- A token is roughly 0.75 words or 4 characters of text. A 1,000-word document is approximately 1,300 tokens. Both your prompt (input) and the model's response (output) consume tokens and are billed separately, usually at different rates.
- Which OpenAI model is the most cost-effective?
- It depends on your use case. For most production applications, GPT-4o mini ($0.15/M input, $0.60/M output) or GPT-4.1 mini ($0.40/M input, $1.60/M output) offer strong performance at a fraction of the cost of flagship models. Use this calculator to compare costs at your actual request volume.
- How much does Claude cost compared to GPT-4o?
- Claude Sonnet 4.6 ($3.00/M input, $15.00/M output) is priced similarly to GPT-4o ($2.50/M input, $10.00/M output) for standard usage. Claude Haiku 4.5 ($1.00/M input, $5.00/M output) is comparable to GPT-4o mini. Use the comparison tool to estimate cost at your specific token volumes.
- Can I reduce my OpenAI or Anthropic bill?
- Yes. The most effective strategies are: (1) switching to a smaller model for simpler tasks, (2) using prompt caching to avoid re-sending the same context, (3) using the Batch API for non-real-time workloads (typically 50% cheaper), and (4) identifying which customers or features are consuming the most tokens — which is what PerUnit is built to help with.
- How accurate is this calculator?
- This calculator uses official standard-tier pricing from OpenAI and Anthropic. Actual costs may be lower if you use prompt caching, batch processing, or have negotiated volume discounts. Always verify against your provider's billing dashboard for production workloads.