Understanding MTTD
How we calculate. MTTD = sum of (start → detect) times ÷ number of incidents. The form uses the same arithmetic as the worked examples on this page. See our methodology and accuracy policy.
Real-world scenario: A typical MTTD case uses total detect time 180 and incidents 12. Enter the same figures below to reproduce the worked path.
What is MTTD?
A detection-speed metric that complements MTTR. Faster MTTD usually shrinks customer impact even before restore starts.
- Start clock = incident begin per policy
- End clock = detect/ack/alert
- Same unit for total time (minutes/hours)
The Formula
Worked Example
Common Use Cases
- Observability reviews: alert coverage
- On-call quality: silent failure risk
- SRE scorecards: detect vs restore
Pro Tips
- Exclude synthetic-only noise if policy says so
- Segment by severity
- Pair with MTTR and MTBF
Limitations: MTTD results are educational DevOps/SRE/FinOps planning aids—not SLAs, billing guarantees, or operational policy. Confirm definitions with your platform and finance teams.
FAQ
Is MTTD part of DORA?
No—DORA’s restore metric is MTTR. MTTD is a common SRE companion for detection latency.
What if incidents is 0?
MTTD is undefined—enter at least one incident.
Authoritative References
For SRE and FinOps definitions, consult:
- Google SRE books — SLOs, error budgets, toil
- DORA — delivery performance research
- FinOps Foundation — cloud cost practices