Excel Destination Column Styles
The most common and useful implementations of Excel format codes are:
Format Code 
Description 
General 
General number format 
# 
Digit placeholder that represents optional digits and does not display extra zeros. 
0 
Digit placeholder that displays insignificant zeros. 
? 
Digit placeholder that leaves a space for insignificant zeros but doesn't display them. 
@ 
Text placeholder 
. (period) 
Decimal point 
, (comma) 
Thousands separator. A comma that follows a digit placeholder scales the number by a thousand. 
\ 
Displays the character that follows it. 
" " 
Display any text enclosed in double quotes. 
% 
Multiplies the numbers entered in a cell by 100 and displays the percentage sign. 
/ 
Represents decimal numbers as fractions. 
E 
Scientific notation format 
_ (underscore) 
Skips the width of the next character. It's commonly used in combination with parentheses to add left and right indents, _( and _) respectively. 
* (asterisk) 
Repeats the character that follows it until the width of the cell is filled. It's often used in combination with the space character to change alignment. 
[] 
Creates conditional formats. 
Symbol 
Description 
+ and  
Plus and minus signs 
( ) 
Left and right parenthesis 
: 
Colon 
^ 
Caret 
' 
Apostrophe 
{ } 
Curly brackets 
< > 
Lessthan and greater than signs 
= 
Equal sign 
/ 
Forward slash 
! 
Exclamation point 
& 
Ampersand 
~ 
Tilde 
Space character 
Excel Number Format
Excel number format consists of 4 sections of code separated by semicolons in the following order:
POSITIVE; NEGATIVE; ZERO; TEXT
Example:
In this example, positive numbers will display 2 decimal places and a "thousands separator." Negative numbers will appear the same as positive numbers but enclosed in parenthesis. Zeros will be replaced as dashes, and the text will be displayed in the magenta color.
Digit and Text Placeholders
Code 
Description 
Example 
0 
Digit placeholder that displays zeros. 
#.00  will display 2 decimal places. A cell that contains 1.2 will be displayed as 1.20. 
# 
Digit placeholder that represents optional digits (does not display extra zeros.) 
#.##  displays up to 2 decimal places. 1.2 will be displayed as 1.2 1.236 will be displayed as 1.24 
? 
Digit placeholder that leaves a space for insignificant zeros on either side of the decimal point but doesn't display them. (Often used to align numbers in a column by decimal point.) 
#.???  displays a maximum of 3 decimal places and aligns numbers in the column by decimal point. 
@ 
Text placeholder 
0.00; 0.00; 0; [Green]@  applies the green font color to text values. 
General 
#,### 
#, 
#.00, 
#.00,, 
50 
50 
.05 
.00 

500 
500 
1 
.50 
.00 
5000 
5,000 
5 
5.00 
.01 
55500 
55,500 
56 
55.50 
.06 
555500 
555,500 
556 
555.50 
.56 
General 
#.00, \K 
#,###.0, \K 
#.00,, \M 
#,###.0000,, \M 
50 
.05 K 
.1 K 
.00 M 
.0001 M 
500 
.50 K 
.5 K 
.00 M 
.0005 M 
55500 
55.50 K 
55.5 K 
.06 M 
.0555 M 
5555000 
5555.00 K 
5,555.0 K 
5.56 M 
5.5550 M 
5555000000 
5555000 K 
5,555,000.0 K 
5555.00 M 
5,555.0000 M 
Temperatures
#"°F" displays Fahrenheit (Example: 85°F)
#"°C" displays Celcius (Example: 23°C.)
Display Leading Zeros
Users can add the number zero (0) as a placeholder to indicate the number of leading zeros.
Example: Adding 00000 to the style will display the number 55 as 00055
Percentages
Add the percent sign (%) to the style format box.
Example: #% will display the number 0.08 as 8%.
Fractions
For decimal numbers to appear as fractions, add the forward slash (/) to the style format box.
Example: #/# will display the number .5 as 1/2.
Scientific Notation
To display numbers as scientific notation, add the capital letter E to the style format box.
Example: 00E+00  displays 1,500,500 as 1.50E+06.
Indents
Some users prefer a cell's contents not position against the cell's border. To add an indent, use the underscore (_).
_( adds indent from the left border.
_) adds indent from the right border.
Font Color
Adding the color surrounded by square brackets ([ ]) will format the font to the specified color. (Note: the color code must be the first item in the section. Also, only the following colors can be used  Black, Green, White, Blue, Magenta, Yellow, Cyan, and Red.)
Example: [Blue] $#,##0.00 will display the number 25.3 as $25.30
Repeat Characters
To repeat a specific character so that it fills the column width, use the asterisk (*) before the character to be repeated.
Example: * will make the cell with the number 555 appear as 555
Alignment
To align numbers left in a cell, type an asterisk and a space after the number code. Example: "#,###* " (Exclude the double quotes when adding the format.)
Custom Number Formats Based on Conditions
To apply conditions that must be met for a custom style, enclose the condition within square brackets.
Example: [Red] [<100] ; [Blue] [>=100] will display numbers as 49 and 184
Custom Date
Format 
Description 
Example (January 1, 2018) 
m 
Month number without a leading zero 
1 
mm 
Month number with a leading zero 
01 
mmm 
Month name in short form 
Jan 
mmmm 
Month name in full form 
January 
mmmmm 
Month as the first letter 
J 
d 
Day number without a leading zero 
1 
dd 
Day number with a leading zero 
01 
ddd 
Day of the week in short form 
Mon 
dddd 
Day of the week in full form 
Monday 
yy 
Last 2 digits of the year 
18 
yyyy 
All 4 digits of the year 
2018 
Custom Time
Format 
Description 
Example (January 1, 2018) 
h 
Hours without a leading zero 
023 
hh 
Hours with a leading zero 
0023 
m 
Minutes without a leading zero 
059 
mm 
Minutes with a leading zero 
0059 
s 
Seconds without a leading zero 
059 
ss 
Seconds with a leading zero 
0059 
AM/PM 
Periods of the day 
AM or PM 
For more Excel Style information, please refer to this blog post here.