# Calculate values with a formula field

- Product: Clastly
- Category: Fields
- Type: How-to
- Updated: 2026-10-29
- URL: https://www.clastly.com/support/fields/formula/

Add a formula field to display a result calculated from other field values.

## Add a formula field

Add the fields used in the formula to the same collection first. For example, to multiply quantity by unit price, add number fields named Quantity and Unit Price and enter numbers in a record.

1. Touch and hold the collection in the collection list and open :ui[Edit Collection].
2. Tap :ui[Add Field].
3. Choose :ui[Formula] under :ui[Field Type] and enter a :ui[Field Name].
4. Tap :ui[Choose a Calculation]. The formula editor opens.


## Enter a formula

1. Open :ui[Fields] and insert the fields you want to use.
2. Open :ui[Functions] to read a function's description and syntax.
3. Enter the formula and review the examples, result, and validation errors.
4. Return to the field editor and tap :ui[Save]. The formula field's result appears in the record's details.

Use this formula to multiply Quantity by Unit Price:

```formula
multiply({Quantity}, {Unit Price})
```

For the available functions, see [Functions you can use in formulas](https://www.clastly.com/support/fields/formula-functions.md).

Enclose field names in braces. If multiple fields have the same name, you can choose the field to reference when inserting it.

The result recalculates when a source value changes. You can't enter the result directly.

## Resolve formula errors or saving problems

If an error appears, check for deleted field references, division by zero, or circular references. If you can't save, review the validation errors in the formula editor. If you purchased Clastly Pro but can't edit the field, see [Clastly Pro features aren't available after purchase](https://www.clastly.com/support/pro/pro-not-unlocked.md).