WebCheck calculates uptime from completed monitoring runs stored by the checker. Public widgets and authenticated site views use the same canonical calculation.
What counts as available?
Passed and degraded checks count as available. A degraded response is slower than expected but is not automatically downtime. Failed and blocked checks count as unavailable.
Why might a new site show current availability?
A site cannot honestly claim a completed 24-hour, 7-day or 30-day percentage before that period has elapsed. During the build-up period WebCheck shows a clearly labelled current availability value instead.
How incidents are confirmed
Transient failures are retried before an outage is recorded. WebCheck retries transient failures every 10 seconds for up to 60 seconds, while security-policy blocks are not bypassed or repeatedly retried.