Regular Expressions Cheat Sheet & Guide

Regular Expression Basics

Regular expressions (regex) are patterns used to match character combinations in strings.

Character Classes

Pattern	Matches
.	Any character except newline
\d	Any digit (0-9)
\w	Word character (a-z, A-Z, 0-9, _)
\s	Whitespace
[abc]	a, b, or c
[^abc]	Not a, b, or c

Quantifiers

Pattern	Matches
*	0 or more
+	1 or more
?	0 or 1
{3}	Exactly 3
{3,5}	Between 3 and 5

Common Patterns

Email validation

^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$

URL matching

https?:\/\/(www\.)?[-a-zA-Z0-9@:%._+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_+.~#?&//=]*)

Password strength (8+ chars, upper, lower, digit, special)

^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$

Try patterns in our Regex Tester.