> ## Content Index
> Fetch the complete content index at: https://blog.jestor.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# How to Use Formula Fields to Calculate Values Automatically
- URL: https://blog.jestor.com/formulas-to-calculate-fields/
- Published: 2026-09-17T22:29:54.000Z
- Updated: 2026-09-17T22:29:54.000Z
- Author: Bruno Bannach

**Formula fields** calculate a value from other fields on the same record. Interest on a late payment, a due date derived from an issue date, a total from quantity and price — all computed rather than typed.

## What manual calculation costs

Every calculated value typed by hand is a value that can be wrong and will eventually be out of date.

- Totals recalculated after every change
- Due dates counted on a calendar
- Interest applied inconsistently across records
- Numbers that disagree with the fields they came from

## Two common formula patterns

| Pattern             | How it works                      | Example                          |
| ------------------- | --------------------------------- | -------------------------------- |
| **Multiplication**  | A value multiplied by a factor    | Amount × 1.10 for a 10% late fee |
| **Date arithmetic** | A date offset by a number of days | Due date = issue date + 15 days  |

## How to configure it in Jestor

1. Add a column in **Jestor** and choose the formula field type.
2. Name it clearly — "amount with late interest", for example.
3. Search for the source field and reference it in the formula.
4. Apply the operation — an asterisk multiplies, so amount × 1.10 adds ten percent.
5. For dates, set the return type to date and use a date-addition function with the source field and the number of days.

## Why choose Jestor for calculated data?

**Jestor** offers field suggestions and function search inside the formula editor, so building one does not require memorizing syntax.

Formulas only work on fields that hold real values, which is why monetary amounts belong in a currency field rather than text — a formula cannot sum text.

## Frequently Asked Questions

### Can a formula return a date?

Yes, by setting the return type and using a date function. See [jestor.com](https://jestor.com/?ref=blog.jestor.com).

### Can formulas reference other fields?

Yes, fields can be searched and inserted directly.

### Why does my formula not sum?

The source field is probably text rather than a number or currency field.

## Video Tutorial: Step by Step

Check out other practical tutorials on the Jestor YouTube channel.

## Get to know Jestor

With **Jestor**, you can automate workflows, connect teams, and build internal systems your way — all without code and powered by **AI**. Discover Jestor at [jestor.com](https://jestor.com/?ref=blog.jestor.com) and see how to take your company's operations to a new level of efficiency and control.