1-Formats

Stored     | Format code              | What Excel displays (truth)
-----------+--------------------------+----------------------------
15%        | 0%                       | 15%                        
12.34%     | 0.00%                    | 12.34%                     
1,234.50   | #,##0.00                 | 1,234.50                   
1,234,567  | #,##0                    | 1,234,567                  
(1,234.50) | #,##0.00;[Red](#,##0.00) | (1,234.50)                 
1.23E-05   | 0.00E+00                 | 1.23E-05                   
007        | 000                      | 007                        
1/2        | # ?/?                    | 1/2                        
3.14       | 0.00                     | 3.14                       
$1,234.56  | "$"#,##0.00              | $1,234.56                  
100.00%    | 0.00%                    | 100.00%

2-DatesTimes

Kind         | Stored value        | Format           | What Excel displays
-------------+---------------------+------------------+--------------------
Date         | 2026-04-21          | yyyy-mm-dd       | 2026-04-21         
Datetime     | 2026-04-21 14:30:00 | yyyy-mm-dd hh:mm | 2026-04-21 14:30   
Time         | 9:45:15             | hh:mm:ss         | 09:45:15           
Duration 49h | 49:30               | [h]:mm           | 49:30              
Old date     | 1900-03-01          | yyyy-mm-dd       | 1900-03-01

3-Merged

Region        | Product | Revenue |     | 2x2 Header
--------------+---------+---------+-----+-----------
North America | Widget  | 1000    |     |           
              | Gadget  | 2000    |     |           
              | Gizmo   | 3000    |     |           
EMEA          | Widget  | 500     |     |           
              | Gadget  | 800     |     |           
              |         |         |     |           
GRAND TOTAL   |         |         |     |

4-Links

Label        | Target                  
-------------+-------------------------
Our website  | https://www.example.com 
Internal ref | #Sheet1!A1              
Email us     | mailto:hello@example.com

5-Comments

Revenue Q1 [note: Auditor: Includes the Marlow-Chen deal (est. $2M)] | 12500000
---------------------------------------------------------------------+---------
Headcount [note: HR: 42 confirmed, 3 pending offers]                 | 42

6-Styles

Red text | Highlighted
---------+------------
Bordered |

7-LineBreaks

Kind           | Value            
---------------+------------------
LF in cell     | line1
line2
line3
Text with \r\n | before
after

8-Formulas

Formula | Expected value  
--------+-----------------
        | #ERR:#DIV/0!    
        | #ERR:#N/A       
        | Depends on above
        | A1 of this sheet
        | #ERR:#NUM!

9-Validation

Status | Score
-------+------
Open   | 5    
Closed | 10

10-Conditional

5  
---
10 
15 
20 
25 
30

11-Hidden

visible1          | also visible | HIDDEN_COL_SECRET
------------------+--------------+------------------
HIDDEN_ROW_SECRET |              |                  
visible2          |              |                  
visible3          |              |

12-VeryHidden

VERY_HIDDEN_CONTENT — should normally not surface in UI  
---------------------------------------------------------

13-NamedRanges

100
---
200
300

14-MessyHeader

                          |      |      |     
--------------------------+------+------+-----
QUARTERLY REPORT — 2026   |      |      |     
                          |      |      |     
Metric                    | Jan  | Feb  | Mar 
Revenue                   | 1000 | 1200 | 1100
Costs                     | 800  | 900  | 950