Data Types

A Data Type refers to how the data is stored in memory and how much space it takes up.
The data type of a variable (or object) tells the compiler the size of the object (ie the number of bytes to use).
You should always try and use the data type that uses the smallest number of bytes to get the job doen.
It is always best to use the data type that uses the smallest amount of space (i.e. bytes) yet can still handle all the data assigned to it.
The data type of a variable determines how the value is represented in memory.
The smaller the bytes the faster it executes.
You should use the data type conversion functions instead of using the Val() function when you want to convert from one data type to another.
All variables must have an associated data type which determines what data can be stored in it.

Data Type	CType	Default	Range	Size	Abr.	(Prefix) Comments
Boolean	CBool	False	True (-1) or False (0)	2 bytes (16 bits)		(b) The zero value is treated as False All other values are treated as True. Use NOT to toggle
Byte	CByte		0 to 255	1 byte (8 bits)		(by) integers often used in conjunction with string operations Use Long instead
Currency	CCur	0	- 9.2 E+14 to + 9.2 E+14	8 bytes (64 bits)	@	(c) scaled integer Use Double instead
Date	CDate		Jan 1 100 to Dec 31 9999	8 bytes (64 bits)		(dt) floating point numbers Use Long instead
Decimal*	CDec		- 7.9 E+28 to + 7.9 E+28	14 bytes		(dec) Variant subtype Must be declared as a Variant and then converted.
Double	CDbl	0	- 1.8 E+308 to + 4.9 E+324	8 bytes (64 bits)	#	(db) double precision floating point used for high accuracy
Integer	CInt	0	- 32,768 to + 32,767	2 bytes (16 bits)	%	(i) integer Use Long instead
Long	CLng	0	- 2,147,483,648 to 2,147,483,647	4 bytes (32 bits)	&	(l) long integer
LongLong	CLngLng	0	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	8 bytes (64 bits)		(ll) Added in Office 2010, VBA 7.0
LongPtr	CLngPtr					(lp) Added in Office 2010, VBA 7.0 Long on 32 bit LongLong on 64 bit
Object		Nothing		4 bytes (32 bits)		(ob) stored as a reference to an object.
Single	CSng	0	- 1.3 E+38 to + 1.3 E+38	4 bytes (32 bits)	!	(sng) single precision floating point used when you have fractional numbers Use Double instead
String	CStr	""		10 bytes + length	$	(s) fixed and variable length
User Defined						(ud)
Variant		Empty		16 - 22 bytes	$	(v) any data type, typically used for arrays or variants

Abbreviations

These are also known as Type Declaration Suffixes
It is possible declare variables by appending a special character to the end of the variable name.

Dim iNumber% 'integer