📉 BIA / RTO-RPO Calculator

MTD / MTPD — Maximum Tolerable Downtime / Period of Disruption

The longest a process can be unavailable before consequences become unacceptable. NIST SP 800-34 Rev. 1 uses MTD; ISO 22301 uses MTPD. They describe the same limit.

RTO — Recovery Time Objective

Target time to recover the process after a disruption. Constraint: RTO ≤ MTD.

WRT — Work Recovery Time

Time to validate data and resume normal operations after systems are back. NIST SP 800-34 relates the three as MTD = RTO + WRT, so WRT = MTD − RTO and RTO + WRT ≤ MTD.

RPO — Recovery Point Objective

Maximum tolerable data loss as a time window back from the disruption; drives backup / replication frequency. Should be within your acceptable data-loss window.

Criticality score

For each time band, the worst-case severity across the four impact areas is multiplied by the band weight (1h=5, 4h=4, 24h=3, 72h=2, 1w=1) and summed, then normalised to 0-100. The tier is set by the peak severity: 5→Critical, 4→High, 3→Moderate, 1-2→Low, 0→Minimal.

Sources: NIST SP 800-34 Rev. 1, Contingency Planning Guide for Federal Information Systems (defines MTD, RTO, RPO, WRT); ISO 22301, Business continuity management systems (defines MTPD, MBCO).

Planning aid only. This tool derives and checks recovery parameters from the values you enter and uses standard terminology; it does not assess, certify or claim compliance with any standard or regulation. Validate results with your continuity team.