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# Formula Field or Automation: Which Should Calculate?
- URL: https://blog.jestor.com/formula-field-or-automation/
- Published: 2026-09-17T22:37:40.000Z
- Updated: 2026-09-17T22:37:40.000Z
- Author: Bruno Bannach

Choosing between a **formula field or automation** comes down to whether the value should follow its inputs forever or be fixed at a moment in time.

## Why the distinction matters

Both produce a number. They behave differently when the inputs change afterwards.

- A formula recalculates whenever its inputs change
- An automation writes a value once, and it stays
- A historical figure that silently updates is misleading
- A live figure that stopped updating is equally misleading

## When to use each

| Situation                         | Use                                                |
| --------------------------------- | -------------------------------------------------- |
| **Total from quantity and price** | Formula — it should follow the inputs              |
| **Hour balance remaining**        | Formula — it changes as work is logged             |
| **Exchange rate applied**         | Automation — fixed at the moment of the decision   |
| **Value at approval**             | Automation — the historical figure should not move |

## How to configure it in Jestor

1. Use a formula field in **Jestor** where the value should always reflect current inputs.
2. Use an automation to write a value that must stay fixed from that moment.
3. Confirm the source fields are the right type — formulas cannot calculate on text.
4. Use formula blocks on panels where the calculation belongs to the view rather than the record.
5. Check the execution log after configuring an automation-written value.

## Why choose Jestor for calculated values?

**Jestor** offers formulas at field level and at panel level, which lets a calculation live with the record when it belongs there and with the view when it does not.

Because the change history records what wrote each value, a figure that moved unexpectedly can be traced to whether a formula recalculated or an automation overwrote it.

## Frequently Asked Questions

### Does a formula update automatically?

Yes, whenever its inputs change. See [jestor.com](https://jestor.com/?ref=blog.jestor.com).

### How do I fix a historical value?

Have an automation write it at the relevant moment.

### Why will my formula not calculate?

The source field is probably text.

## 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.