Timestamped downtime summary · user-provided records
Uptime incident log calculator
Calculate downtime and observed availability from timestamped incident intervals within a chosen measurement window. Merge overlaps and optionally exclude planned rows; no monitoring or SLA interpretation.
Summarize timestamped incident intervals you already recorded. This local worksheet does not monitor a site, validate incident reports, or determine whether an outage qualifies under an SLA.
Enter a window and zero or more incident intervals.
Input and calculation rules
- Use one ISO 8601 timestamp with a timezone on each side of a comma, such as
2026-10-05T10:00:00Zor2026-10-05T10:00:00+02:00. The window start must be before its end; each incident start must be before its end. - Append
,plannedto mark a planned-maintenance interval. The checkbox excludes those tagged intervals from the selected result. With it unchecked, all intervals count. Planned status is your classification, not an SLA ruling. - Intervals are clipped to the measurement window. Overlapping intervals are merged before counting, so the same minute is never counted twice. With planned rows excluded, overlap from a separately logged unplanned incident still counts as downtime.
- Observed availability = (window duration − included incident downtime) ÷ window duration × 100. The result assumes the log is complete and its intervals accurately represent your chosen service and measurement point.
This is a summary of entered incident records, not a monitoring system or an uptime guarantee. It cannot detect missing incidents, failed checks between observations, partial outages, latency, regional differences, or the provider's contract rules. Compare your monitoring method and SLA definitions before using a result in a claim.
Sources
- Cloudflare: Application availability — explains uptime, downtime, and availability as a proportion over a measurement period; checked November 3, 2026.
- Python standard library: datetime — reference for ISO 8601 date-time forms and timezone offsets; the browser tool accepts a narrower subset requiring an explicit timezone; checked November 3, 2026.
For a theoretical conversion from an SLA percentage to downtime minutes, use the uptime SLA downtime calculator. It does not measure incidents.
How it works
Enter a measurement window and paste one timezone-qualified ISO 8601 start/end interval per line. Add planned to a row to identify maintenance, then choose whether to exclude those rows from the selected availability result. Overlaps merge and intervals clip to the window.
Good to know
How are overlapping incidents counted?
The calculator merges overlapping intervals before summing downtime, so a minute is counted at most once. It clips each interval to the selected measurement window.
Can I exclude planned maintenance?
Yes. Add planned as the third comma-separated field on a row and check the exclusion option. This is your classification; it does not determine how a particular SLA treats maintenance.
Does this prove my host's uptime or SLA result?
No. It summarizes only the incident intervals you provide. It does not monitor a site, detect missing incidents, or apply a provider's measurement rules or exclusions.
Impact — TODO: apply/approval and configure referral URL — referral link not configured.
CJ Affiliate — TODO: apply/approval and configure referral URL — referral link not configured.
PartnerStack — TODO: apply/approval and configure referral URL — referral link not configured.