# Formulas

A **formula field** contains a value calculated from a spreadsheet-like expression. Formulas operate on other fields on the same record — including other formula fields — supporting mathematical, logical, text, and date-based processing. For example, a *full name* field on the **User** table could concatenate the *first name* and *last name* fields.

This page covers the concept and lifecycle. For task and reference content, see:

* [Creating a formula field](/data/collections/formulas/creating-formula-fields.md) — step-by-step setup
* [Examples](/data/collections/formulas/examples.md) — common formula recipes
* [Troubleshooting](/data/collections/formulas/troubleshooting.md) — fixing formulas that don't work
* [Operators reference](/data/collections/formulas/operators.md) — all supported operators, grouped by category:
  * [Date & time operators](/data/collections/formulas/operators/date-and-time.md)
  * [Logic operators](/data/collections/formulas/operators/logic.md)
  * [Math operators](/data/collections/formulas/operators/math.md)
  * [Text operators](/data/collections/formulas/operators/text.md)

### When do formulas calculate?

A formula's value for a given record recalculates when any of the following occur:

* The formula field is created
* The formula is updated
* A new record is added
* A field referenced in the formula is updated

If a formula doesn't reference any other fields, it will only recalculate when:

* The formula is added initially
* The formula is edited
* The record is initially created

### Output types

When a formula is added or updated, Noloco inspects the output and assigns a type based on the result pattern. The possible output types are:

* **Boolean** — formula must return `true` or `false`
* **Date** — formula must return a value wrapped in the `TODATE` operator
* **Decimal**
* **Integer**
* **Text**


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