What domain age tells you
A domain's age is the time since it was first registered, taken from the creation date in the registry's record. This checker reads that date from the registry's public RDAP data, so it's the official figure rather than an estimate from archive snapshots.
Age is a useful trust signal. A shop that claims ten years in business on a domain registered last month deserves a second look, and phishing sites are almost always freshly registered. When you're buying a domain or a website, the age, registrar and expiry together tell you whether it has been held continuously.
Age on its own is not a Google ranking factor; Google has said so directly. Older domains tend to rank because they've had years to earn links and content, not because of the date itself. If the domain was dropped and re-registered, the creation date resets, and so does any history a buyer was paying for.