# AI Inference

> Inference is the act of running a trained AI model to produce an output, as opposed to training, which is building the model in the first place. Every time you send a prompt and get an answer, that is one inference. It is where the ongoing cost, speed, and energy use of AI mostly live.

- Updated: 2026-06-23
- Canonical: https://geotoolbox.ai/glossary/ai-inference

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Pretraining a frontier model is an enormous upfront expense; inference is the recurring one, paid every time anyone asks the model anything. That economics shapes the products you use: free tiers route you to fast, cheap models, daily caps exist because inference costs money, and architectures like [mixture of experts](https://geotoolbox.ai/glossary/mixture-of-experts) exist largely to make inference cheaper.

It also explains why engines do not re-read the whole web for every query. Inference has a budget, so an AI answer pulls a handful of retrieved sources, not hundreds. Being one of the few clear, authoritative pages on your topic is worth more than being one of many vague ones, because only a few make it into the answer.