Ask the person directly
Check their public social media profiles (about/bio, posts, birthday reminders)
Look for birthday entries on professional profiles (LinkedIn, company directory)
Search their website or newsletter sign-up confirmation pages (if they list birthdays)
Check shared calendars or contacts where birthdays are enabled
Search mutual friends’ posts for birthday announcements
Review event invitations or group chat messages mentioning their birthday
Use a people-search directory that includes birthdays (only if provided publicly)
Ask mutual acquaintances if they are comfortable sharing
Check public records or official sources where permitted and available
Avoid guessing, scraping, or accessing private accounts without consent