LLM API cost calculator
Estimate the monthly cost of calling Claude, GPT or Gemini. Enter your typical request size and volume, pick a model, and see the cost per request, day, month and year.
Prices last verified against official provider pages on . How we verify prices. Written by the Chelure Enterprises Editorial Team.
How the calculation works
For each request the calculator computes input cost (input tokens ÷ 1,000,000 × input price) plus output cost (output tokens ÷ 1,000,000 × output price). If you enter a cache percentage, that share of your input tokens is billed at the model's cached-input rate instead. Where a provider lists no cached rate for a model, the full input price is used.
Totals use a 30-day month. If you enter requests per month, the daily figure is the monthly figure divided by 30.
A worked example
Take a support chatbot that sends about 1,500 input tokens and receives about 400 output tokens per request, with 1,000 requests a day and no caching. At today's prices that comes to about $210.00 a month on Claude Sonnet 5.5, about $210.00 on GPT-6.1 Sol, and about $78.75 on Gemini 3.8 Flash. Switching to a smaller model in the same family usually cuts the bill several-fold, so it is worth testing whether a cheaper model is good enough for your task before optimizing anything else.
Ways to lower your bill
- Cache repeated prefixes. System prompts and reference documents that appear in every request are the best candidates.
- Trim output. Output tokens cost the most. Ask for concise answers or structured fields instead of long prose.
- Use batch where the work can wait. Anthropic lists a 50% discount for its Batch API. Check each provider for its own batch terms.
- Right-size the model. Route easy requests to a small model and reserve the large one for hard cases.
Tokenizers differ by provider. Anthropic states that Claude 4.7 and later models use a newer tokenizer that produces about 30% more tokens for the same text than earlier Claude models, so token counts are not directly comparable between families. Use the token counter for a rough estimate of your own text.
Frequently asked questions
How do I calculate LLM API cost?
Multiply input tokens by the input price and output tokens by the output price, each divided by one million, then add them. Multiply by the number of requests. This calculator also handles cached input and, for Claude, batch pricing.
Why are output tokens more expensive than input tokens?
Every provider listed here charges more for output than input, typically four to eight times more. Generating tokens takes more compute than reading them, so a reply-heavy workload costs more than a read-heavy one with the same total token count.
What is cached input?
Prompt caching lets you reuse a long, repeated prefix such as a system prompt or document. Cached reads are billed at a fraction of the normal input price. The percentage field on this calculator estimates the share of your input tokens served from cache.
Are the prices on this page official?
They are copied from the providers' own pricing pages and re-verified on the date shown at the top of the page. Providers change prices, so confirm on their site before you commit to a budget.
Cite this page: LLM API cost calculator. Createchz AI Tools, verified November 13, 2026. https://createchz.com/ai-costs/llm-api-cost-calculator/