Domain age is simply how long a domain has existed since it was first registered, checkable through free WHOIS lookup tools that show the registration date along with other ownership details.
Google has said directly that domain age itself is not a ranking factor, and the correlation people often point to (older sites tend to rank well) is mostly explained by what age gives a site time to accumulate: backlinks, content, brand recognition, and a track record of staying online and staying updated. A brand-new domain with excellent content and a genuine link profile can outrank an old, neglected one, but it starts from a real disadvantage in trust signals that simply take time to build regardless of quality. That's the practical takeaway: age isn't the lever to pull, but the things age tends to correlate with are, which is why a new domain benefits from investing early and consistently rather than waiting for time alone to help.
