Personal data is any information that can be used—alone or combined with other details—to identify a living person or describe aspects of that person’s life. Laws like the GDPR in Europe and UK GDPR define it very broadly, covering both obvious identifiers and more indirect clues.

Core definition

  • Personal data is information about an identified or identifiable natural person (a human being, not a company).
  • A person is identifiable if you can single them out directly (by name) or indirectly (by combining other details).
  • Even data that has been pseudonymised (like replacing a name with a code) is still personal data if it can be linked back to someone.

Obvious examples

These are the kinds of details most people immediately think of as personal data.

  • Name and surname
  • Home or email address
  • Phone number
  • Identification numbers (passport, ID, social security, student number)
  • Location data (GPS coordinates, precise home/work location)
  • Online identifiers like IP address, device ID, or tracking cookies when they tie back to a user profile.

Less obvious but still personal

Many details count as personal data because they relate to someone’s identity, even if they don’t look like a “name tag.”

  • Biometric data: fingerprints, facial recognition templates, voiceprints, DNA.
  • Physical and mental characteristics: age, disability status, height, medical conditions.
  • Economic and social information: salary, debts, purchase history, job title, education, social media profiles.
  • Opinions and preferences: political views, product reviews linked to an account, likes and follows on platforms.

Direct vs indirect identification

  • Direct identification : Data that points straight to a person, like “Alex Kim, born 1990, living at 12 Oak Street.”
  • Indirect identification : Pieces that might not name you, but combined can clearly identify you, like “the doctor living at 11 Belleville Street whose son is in Class 3B.”

Even anonymised-looking data can become personal if it can be reconnected to an individual using other information.

Why personal data matters now

  • In today’s data-driven economy, personal data powers targeted ads, personalization, credit scoring, and even some AI models.
  • Misuse or breaches can lead to harms like identity theft, discrimination, or unwanted profiling, which is why modern privacy laws set strict rules for collecting, using, and storing it.

TL;DR: Personal data is any information that identifies you or can be combined with other data to identify or describe you—names, IDs, online traces, biometrics, and even patterns of behaviour all count.