AI Prompt Cost Estimator
Paste your prompt, set expected output length, and instantly compare API costs across all major models. Plan your monthly budget with bulk estimates.
0 tokens (0 words)
Bulk Estimate
| Model | Provider | Input /1M | Output /1M | Cost / Call | Monthly | Bar |
|---|---|---|---|---|---|---|
| GPT-4o | OpenAI | $5.00 | $15.00 | — | — | |
| GPT-4o mini | OpenAI | $0.150 | $0.600 | — | — | |
| o1 | OpenAI | $15.00 | $60.00 | — | — | |
| o1 mini | OpenAI | $3.00 | $12.00 | — | — | |
| Claude 3.5 Sonnet | Anthropic | $3.00 | $15.00 | — | — | |
| Claude 3.5 Haiku | Anthropic | $0.800 | $4.00 | — | — | |
| Claude 3 Opus | Anthropic | $15.00 | $75.00 | — | — | |
| Gemini 1.5 Pro | $3.50 | $10.50 | — | — | | |
| Gemini 1.5 Flash | $0.075 | $0.300 | — | — | | |
| Gemini 2.0 Flash | $0.100 | $0.400 | — | — | |
Prices as of Q1 2025. Verify at each provider's pricing page. Input token count uses 0.75 tokens/word approximation.
Frequently Asked Questions
How are API costs calculated?▼
LLM APIs charge separately for input tokens (your prompt + context) and output tokens (the model's response). Costs are priced per 1 million tokens. For example, GPT-4o at $5/1M input means 1,000 tokens costs $0.005. Total cost = (input_tokens / 1M × input_price) + (output_tokens / 1M × output_price).
Why is output more expensive than input?▼
Output tokens require the model to generate each token auto-regressively — a compute-intensive process. Input tokens are processed in parallel via attention mechanisms. Generating output is typically 3–5× more compute-intensive per token, which is reflected in the pricing.
How do I estimate token count?▼
A rough rule: 1 token ≈ 0.75 words in English, or about 4 characters. For exact counts, use the tokenizer tool for the specific model (e.g., OpenAI's tiktoken for GPT models). Our estimator uses the 0.75 words/token approximation for quick calculations.
What is a 'bulk estimate'?▼
The bulk section calculates monthly costs assuming a fixed number of identical API calls per day. It's useful for planning production API budgets — for example, estimating the cost of a chatbot that handles 10,000 conversations per day, each with a 500-token prompt and 300-token response.
Are these prices current?▼
Prices shown reflect Q1 2025 rates and may change. Always verify current pricing at platform.openai.com/pricing, anthropic.com/pricing, and ai.google.dev/pricing. Prices frequently drop as competition increases.
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