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Calcimator

Network Uptime Calculator

Calculate network availability percentage from MTBF, MTTR, component count, and redundancy level. Shows downtime in hours/minutes per year.

Inputs

hours
hours

Results

Availability

99.96 %

Nines of Availability

3.4

Downtime per Year

3.51 hours

Downtime per Month17.53 min
Downtime per Week4.04 min
Single Component Avail.99.992 %
Series Path Avail.99.96 %
Expected Failures/Year0.88
Sla LevelThree 9s (99.9%)
How to Use This Calculator
  1. Enter MTBF (Mean Time Between Failures), MTTR (Mean Time to Repair), and Components in Series.
  2. Set Redundant Paths.
  3. Review Availability (%), Nines of Availability, and Downtime per Year (hours).
  4. Use Downtime per Month (min) and Downtime per Week (min) to inform your decision.
  5. Use the chart to visualize the results and explore different scenarios by adjusting inputs.

How the result changes with Redundant Paths

Redundant PathsAvailabilityNines of AvailabilityDowntime per Year
1.399.9962 %4.420.34 hours
2.05100 %6.970 hours
2.95100 %10.020 hours
3.7100 %12.570 hours

What each input means

MTBF (Mean Time Between Failures)
Average time between failures for each component (from manufacturer specs)
MTTR (Mean Time to Repair)
Average time to diagnose and repair a failure (4-hour SLA common)
Components in Series
Number of non-redundant components in the path (all must work)
Redundant Paths
Number of parallel paths (1=no redundancy, 2=dual active/standby)

How this is calculated

Formula

A = MTBF/(MTBF+MTTR); Series = A^n; Parallel = 1-(1-A_series)^paths

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    MTBF (Mean Time Between Failures) = 50000, MTTR (Mean Time to Repair) = 4, Components in Series = 5, Redundant Paths = 1 = 4 input(s) provided
  2. Calculate Availability
    Availability
    99.96 = 99.96
  3. Calculate Nines of Availability
    Nines of Availability
    3.4 = 3.4
  4. Calculate Downtime per Year
    Downtime per Year
    3.51 = 3.51
  5. Calculate Downtime per Month
    Downtime per Month
    17.53 = 17.53
  6. Calculate Downtime per Week
    Downtime per Week
    4.04 = 4.04

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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