Pattern

Regex for 12-hour time (with AM/PM)

12-hour time with AM/PM marker.

The 12-hour time (with AM/PM) regex is ^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$ — copy it below, or open it in the explainer for a token-by-token breakdown.

The pattern

^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$

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What it matches

9:30 AM
12:00 PM
11:59pm
1:05 AM

What it doesn't match

13:00 PM
9:30
9:30 ZM
0:30 AM

Notes & gotchas

Hours 1–12, AM or PM (case-insensitive). Space before AM/PM is optional. Use the /i flag if you want strict case insensitivity for the marker.

Code in your language

Use the explainer's Code tab to generate ready-to-paste snippets in JavaScript, Python, Java, .NET, Go, Ruby, and PHP for this pattern.

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Token-by-token breakdown

Every part of the pattern, left to right:

Token	Meaning
`^`	start of string (or line in multiline mode)
`(`	start of a capturing group
`0?`	optional (zero or one): the literal “0”
`[1-9]`	any of: 1–9
`\|`	OR — try the alternative
`1`	literal text “1”
`[0-2]`	any of: 0–2
`)`	end of group
`:`	literal text “:”
`[0-5]`	any of: 0–5
`\d`	any digit (0–9)
`\s?`	optional (zero or one): whitespace
`(`	start of a capturing group
`AM`	literal text “AM”
`\|`	OR — try the alternative
`PM`	literal text “PM”
`\|`	OR — try the alternative
`am`	literal text “am”
`\|`	OR — try the alternative
`pm`	literal text “pm”
`)`	end of group
`$`	end of string (or line in multiline mode)

About this pattern

Date and time formats vary enormously across regions and systems. The regex here validates structure only — a date like 2024-02-30 would pass format validation but isn't a real date. After regex passes, parse with your language's date library to confirm semantic validity.

Quick usage in different languages

This exact pattern — with the correct escaping and idioms for each language:

JavaScript: /^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$/.test(value)
Python: re.match(r"^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$", value)
Java: Pattern.compile("^(0?[1-9]|1[0-2]):[0-5]\\d\\s?(AM|PM|am|pm)$").matcher(value).matches()
C# / .NET: Regex.IsMatch(value, @"^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$")
Go: regexp.MustCompile(`^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$`).MatchString(value)
Ruby: /^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$/.match?(value)
PHP: preg_match('~^(0?[1-9]|1[0-2]):[0-5]\d\s?(AM|PM|am|pm)$~', $value)

The explainer’s Code tab regenerates these for any pattern you paste, and the downloadable cheat sheet bundles the breakdown, all seven snippets, and the pitfalls below onto one printable page.

Common pitfalls

Anchored to the whole string. This pattern uses ^ and $, so it requires the entire input to match. To find it inside a longer text, drop the anchors and use the global (g) flag.
Escape it correctly per language. In Java and JavaScript strings each backslash must be doubled (\\d); in Python, Go, and C# use raw/verbatim strings so the backslashes survive.
Validate beyond format. Matching the format doesn't guarantee the value is real. Confirm the 12-hour time (with am/pm) against a source of truth (database, API, or checksum) where it matters.

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