How do you calculate tool downtime cost?

Multiply downtime hours by lost margin per hour, scale by the tool-attributable share, then add the flat restart and scrap charge. With 16 hours x $450/hr x 85% + $700, the total is $6,820.

Why apply a tool-attributable share instead of 100%?

Not every minute of a stoppage is the tool's fault. If 15% of the 16 hours was actually waiting on material or an operator, only 85% ($6,120 of variable loss) should be charged to the tool so your reliability case stays credible.

What is the cost per downtime hour in the example?

Total cost of $6,820 divided by 16 downtime hours is roughly $426 per hour. That per-hour figure is the number to compare against the cost of a spare tool or a faster changeover.

Should scrap be in lost margin per hour or the flat charge?

Put ongoing scrap while the line limps at reduced rate into the lost-margin rate, and put one-time first-off scrap, purge, and setup labor from the restart into the $700 flat charge to avoid double counting.

What is a good downtime cost to target?

There is no universal 'good' number; the goal is trend reduction. Track cost per tool per quarter and per downtime hour, and prioritize the tools whose total annual downtime cost exceeds the price of a spare or a redesign.

Tool downtime cost vs. total line downtime cost?

Total line downtime cost charges the full stoppage to production; tool downtime cost isolates only the tool-attributable share, which is what you use to justify tooling budget rather than upstream fixes.

Tooling, Fixtures, Dies & Mold Economics calculator

Tool Downtime Cost Calculator

Tool Downtime Cost quantifies the true dollar impact when a die, mold, or cutting tool takes a press or machining cell offline. It combines the contribution margin the line would have earned, the fraction of the stoppage genuinely caused by the tool (versus operator, material, or upstream issues), and the flat cost to restart and scrap first-off parts. Tooling engineers, maintenance managers, and cost estimators use it to justify preventive tool maintenance, spare-tool inventory, and tool-life improvement projects. Without it, downtime is buried as vague 'lost production' and never wins capital.

What this calculator does

Estimate the production cost of tooling-caused downtime from lost hours and forfeited margin.
A plant quantifies the financial impact of a die failure to prioritize a preventive tooling investment.
It computes the total dollar cost of a tool-related stoppage and the average cost per downtime hour, splitting variable margin loss from the fixed restart and scrap charge.

Formula used

Total downtime cost = downtime hours x lost margin per hour x tool share% + restart flat
Cost per downtime hour = total cost / downtime hours

Inputs explained

Tool-caused downtime duration:
Lost contribution margin per hour:
Tool-attributable share of the stoppage:
Restart, purge & scrap flat charge:

How to use the result

Use it after a tool failure or planned tool swap to build the cost case for spares, hot-runner upgrades, or a PM interval change, and to compare failure modes by dollar severity.
It uses a single blended lost-margin rate; if the tool serves multiple part numbers at different margins, or if the line can partially recover output, the true loss can differ from this straight-line estimate.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 14,378 furniture and related products establishments employing about 355,594 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate tool downtime cost? Multiply downtime hours by lost margin per hour, scale by the tool-attributable share, then add the flat restart and scrap charge. With 16 hours x $450/hr x 85% + $700, the total is $6,820.
Why apply a tool-attributable share instead of 100%? Not every minute of a stoppage is the tool's fault. If 15% of the 16 hours was actually waiting on material or an operator, only 85% ($6,120 of variable loss) should be charged to the tool so your reliability case stays credible.
What is the cost per downtime hour in the example? Total cost of $6,820 divided by 16 downtime hours is roughly $426 per hour. That per-hour figure is the number to compare against the cost of a spare tool or a faster changeover.
Should scrap be in lost margin per hour or the flat charge? Put ongoing scrap while the line limps at reduced rate into the lost-margin rate, and put one-time first-off scrap, purge, and setup labor from the restart into the $700 flat charge to avoid double counting.
What is a good downtime cost to target? There is no universal 'good' number; the goal is trend reduction. Track cost per tool per quarter and per downtime hour, and prioritize the tools whose total annual downtime cost exceeds the price of a spare or a redesign.

Last reviewed 2026-05-12.