Quick answer
Learn the basic uptime and downtime calculations used in service-level reporting and how monitoring timestamps make the numbers easier to prove.
The basic equation
Uptime percentage is commonly calculated as available time divided by total measured time, multiplied by 100. The exact measurement window and what counts as available should be defined in your service-level agreement.
Why exact timestamps matter
Reporting becomes much easier when an external monitor records the moment an incident is detected and the moment the service recovers. That removes the need to reconstruct an outage from memory after the incident.
Do not confuse monitoring data with an SLA itself
A monitoring system can provide evidence, but the SLA defines what counts as an outage, exclusions, maintenance windows, and business commitments. Keep those definitions explicit.
PingStag downtime tracking
PingStag records a downtime start state and calculates the duration when the monitor recovers, allowing the recovery alert to include an outage duration for operational follow-up.
Sources and references
Related PingStag guides
Post-Mortems Made Easy: Tracking Exact Downtime Durations
Why guessing how long a server was offline ruins SLAs, and how exact duration math simplifies reporting.
What Is Website Uptime Monitoring? A Practical Guide
Understand how website uptime monitoring works, what uptime percentages mean, how outages are detected, and where application-level checks go beyond a basic ping.
How to Check If a Website Is Down Right Now
A practical guide to checking website outages, distinguishing local connection problems from real downtime, and deciding when to use external uptime monitoring.
How to Monitor HTTP 500 Internal Server Errors
Learn what HTTP 500 means, why a site can appear intermittently broken, and how to detect recurring server-side failures before customers report them.
