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# How to Use Date Formulas to Add Days or Months and Generate Custom Identifiers and Deadlines
- URL: https://blog.jestor.com/date-formulas-add-days-months-jestor/
- Published: 2026-07-19T02:15:50.000Z
- Updated: 2026-07-19T02:15:50.000Z
- Author: Bruno Bannach

In **Jestor**, the formula field with the **date add** function lets you add days or months to an existing date, useful for automatically generating a due date from an issue date.

## Why calculate deadlines automatically instead of typing them manually?

Typing the due date by hand on every new record creates a risk of error and repetitive work. A formula that adds a fixed interval to the issue date eliminates that manual step.

## How to configure a date formula to add days or months?

| Formula parameter       | Example              |
| ----------------------- | -------------------- |
| **Base date field**     | Issue date           |
| **Interval to add**     | 15                   |
| **Unit (day or month)** | D (day) or M (month) |

## How to build this formula step by step?

1. Add a new formula-type column.
2. Set the result to return a date.
3. Use the **date add** function, selecting the base date field.
4. Enter the interval (e.g., 15) and the unit (D for days, M for months).
5. Save — the calculated field now updates automatically based on the source date.

## Why choose Jestor to automate deadlines and identifiers?

**Jestor** lets formula fields handle both date calculations and text concatenation, covering everything from automatic deadlines to custom identifiers using the same formula tools.

### Does the date formula only work for adding days?

No, the same function accepts both days and months, just by switching the unit.

### Does this field need to be updated manually when the base date changes?

No, the formula field recalculates automatically whenever the base date changes.

### Can date formulas also generate identifiers?

Yes, combined with text concatenation, they can build custom identifiers together with other fields.

### Video Tutorial: Step by Step

Check out more practical tutorials on Jestor's YouTube channel.

### Get to know Jestor

With **Jestor**, deadlines and identifiers are calculated automatically by formula, with no manual entry required.

Get to know Jestor at [jestor.com](https://jestor.com/?ref=blog.jestor.com) and see how to take your operation's efficiency to a new level.