Algorithm, model and app: what is the difference?
These three words are often mixed up, but they describe different things.
What is it?
An algorithm is a step-by-step procedure. A model is the result of training that turns an input into an output. An application is the product that wraps the model with an interface, rules and permissions. The three words are often confused, but they describe different things.
An everyday example
A chatbot is an application. The language model generates the answer. The program around it decides whether it may read a file.
Why does it matter?
When a product makes a mistake, it matters where the mistake arose: in the model, in the application’s rules or in how it was used. That decides who can fix it and who is responsible.
A common misconception
That a product’s abilities are the same as the model’s. The same model can behave very differently in two applications.
In more detail
What is an algorithm?
A sequence of steps for solving a task. An algorithm is not necessarily AI.
What is a model?
A trained or designed system that turns input into output. It can be part of a larger app.
What is an app?
A product that combines an interface, a model, rules, data, tools and safety measures.
Why does the difference matter?
Two apps can use the same model yet behave very differently because of their data, tools and limits.
Remember: What a product can do is not always what its underlying model can do.
Reliable sources
Last reviewed 1 November 2026. An explainer, not professional, legal or medical advice. For rules and figures that change, check the official version.