regex match date — YYYY-MM-DD and common formats

Quick Answer

# ISO 8601 — YYYY-MM-DD
/\b\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])\b/

// JavaScript — extract all ISO dates from text
const text = 'From 2024-01-15 to 2024-12-31';
text.match(/\b\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])\b/g)
// ['2024-01-15', '2024-12-31']

Usage

Extract or validate dates in log files, CSV exports, or form input.

Other causes & fixes

Common date format patterns

# YYYY-MM-DD
/\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])/

# MM/DD/YYYY or MM-DD-YYYY
/(?:0[1-9]|1[0-2])[\/-](?:0[1-9]|[12]\d|3[01])[\/-]\d{4}/

# D Month YYYY  (e.g. "15 January 2024")
/\d{1,2} (?:January|February|March|April|May|June|July|August|September|October|November|December) \d{4}/

Python — parse with datetime instead of regex

For actual date validation (e.g. Feb 30 does not exist), use the datetime library.

from datetime import datetime

def parse_date(s):
    try:
        return datetime.strptime(s, '%Y-%m-%d')
    except ValueError:
        return None

parse_date('2024-01-15')   # datetime(2024, 1, 15)
parse_date('2024-02-30')   # None — invalid date

Extract date components with named groups

import re
m = re.match(r'(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})', '2024-01-15')
m.group('year')   # '2024'