Coachnest — Modern Learning Platform

Data Validation controls what users are allowed to type into a cell — preventing bad data before it happens.

A spreadsheet cell showing a dropdown list of allowed values

Where to Find It¶

Data tab → Data Validation → Settings

Validation Types¶

Allow	Restricts to
Whole number	Integers in a range
Decimal	Numbers in a range
List	A fixed set of choices (dropdown!)
Date	Dates in a range
Text length	A max/min length
Custom	Any formula returning TRUE/FALSE

The most popular use — force users to pick from set values:

1.Select the cells.
2.Data → Data Validation → Allow: List.
3.In Source, type TODO,IN_PROGRESS,DONE (or point to a range =$H$2:$H$5).
4.OK → each cell now has a dropdown arrow.

| Task        | Status ▼  |   ← only TODO / IN_PROGRESS / DONE allowed
| Write docs  | TODO      |

Input Messages & Error Alerts¶

Input Message tab: a tooltip shown when the cell is selected ("Pick a status").
Error Alert tab: the message shown on invalid entry. Choose:
- Stop — blocks the entry entirely.
- Warning — allows after confirmation.
- Information — just notifies.

Custom Validation with a Formula¶

excel

3 lines

1Allow: Custom
2Formula: =A2 > TODAY()        → only future dates accepted
3Formula: =COUNTIF(A:A,A2)=1   → block duplicate entries

Tip

Build dropdowns from an Excel Table column. Because tables auto-expand, new options you add appear in the dropdown automatically — no editing the validation source.

Data Validation & Dropdown Lists

Data Validation & Dropdown Lists¶

Where to Find It¶

Validation Types¶

Creating a Dropdown List¶

Input Messages & Error Alerts¶

Custom Validation with a Formula¶