Downtime Loss Calculator

Purpose

This calculator estimates how much production and contribution margin you lose due to planned and unplanned downtime.

It helps answer: how much downtime is costing per month, per year, and specifically from unplanned events.

Inputs

• Planned Downtime: Scheduled downtime (for example maintenance), entered as time per month.
• Unplanned Downtime: Unexpected downtime (for example breakdowns), entered as time per month.
• Production Rate: Average production speed in units per hour.
• Contribution Margin: Contribution margin per unit (currency per unit). The currency you enter here is used for financial outputs.
• Recovery Rate: Share of lost production recovered through catch-up actions (for example overtime or rescheduling).
• Events per Month: Average number of downtime events per month.
• Cost per Event: Fixed cost per downtime event (for example call-out, restart, and setup losses).

Results

• Total Downtime: Planned plus unplanned downtime.
• Planned Production Loss: Units not produced during planned downtime.
• Unplanned Production Loss: Units not produced during unplanned downtime.
• Production Loss: Total units not produced from all downtime.
• Recovered Production: Units recovered from the gross production loss using the recovery rate.
• Net Production Loss: Production loss after subtracting recovered units.
• Event Cost per Month: Monthly fixed downtime-event cost.
• Financial Loss: Monthly total loss = margin loss after recovery + event cost.
• Annual Financial Loss: Yearly contribution-margin loss from total downtime.
• Cost of Unplanned Downtime: Monthly unplanned downtime cost plus monthly event cost.
• Annual Cost of Unplanned Downtime: Yearly contribution-margin loss caused only by unplanned downtime.

Understanding the Calculation

• Lost production = downtime x production rate
• Recovered production = lost production x recovery rate
• Net production loss = lost production - recovered production
• Margin loss after recovery = net production loss x contribution margin
• Event cost per month = events per month x cost per event
• Financial loss = margin loss after recovery + event cost per month
• Annual values are monthly values converted to per-year units

Example

Using defaults:

• Planned Downtime: 2 hr/mo
• Unplanned Downtime: 5 hr/mo
• Production Rate: 120 unit/hr
• Contribution Margin: 8 USD/unit
• Recovery Rate: 0 pct
• Events per Month: 4 nos/mo
• Cost per Event: 150 USD/nos

Results:

• Production Loss = 840 unit/mo
• Financial Loss = 7320 USD/mo
• Annual Financial Loss = 87840 USD/yr
• Cost of Unplanned Downtime = 5400 USD/mo

Important Assumptions and Interpretation

• Downtime-driven production loss is linear, but total financial loss also includes fixed event costs and recovery effects.
• It uses contribution margin, not full accounting profit.
• It assumes production rate and margin stay constant during the period.
• Recovery is modeled as a single percentage, not by shift-level constraints.
• It does not model bottlenecks or downstream constraints.