eight or more characters with upper, lower and a digit

Q: What is the regex for eight or more characters with upper, lower and a digit?

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

Q: Which strings match?

Text like Passw0rdy matches; text like password does not.

Q: Does the whole string have to match?

Yes. It is wrapped in ^ and $, so nothing but a full match passes.

Q: How do I use what it caught?

There are no capture groups, so only the whole match (match[0]) comes back. Wrap the part you need in brackets to capture it.

Matches eight or more characters with upper, lower and a digit. It is anchored at both ends, so the whole string has to match. There are no capture groups.

Pattern

/^(?=.*[A-Z])(?=.*\d)(?=.*[a-z]).{8,}$/

Match scope: the whole string
Capture groups: 0
What it catches in the first example: Passw0rdy

Try it yourself

Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.

Passw0rdy

1 match

Examples that match

Passw0rdy
A1bcdefg

Examples that do not match

password
PASSWORD1

Other expressions in this group

\d+(?= dollars)a number followed by a certain word ^(?!admin$).+$anything except this one word (?<=\$)\d+a number preceded by a certain sign (?<!\$)\b\d+a number without that sign in front ^(?!.* ).+$text with no double space anywhere ^(?=.*@).+$text that must contain this sign \B(?=(\d{3})+(?!\d))the spot where a thousands comma goes

How to read this

With ^ and $ around it, the whole string must match; without them the match can sit anywhere. Always anchor an expression you use for validation.
Round brackets ( ) capture what they wrap. When you only need grouping, write (?: ) so the numbering of later groups does not shift.
Every expression here is checked against its examples. Even so, "looks like an email" and "is a real inbox" remain different questions.
Nested open-ended repeats such as (a+)+ can blow up on certain inputs. Look for that shape before pasting someone else’s expression into your code.

Frequently asked questions

Q. What is the regex for eight or more characters with upper, lower and a digit?

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

Q. Which strings match?

Text like Passw0rdy matches; text like password does not.

Q. Does the whole string have to match?

Yes. It is wrapped in ^ and $, so nothing but a full match passes.

Q. How do I use what it caught?

There are no capture groups, so only the whole match (match[0]) comes back. Wrap the part you need in brackets to capture it.