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Calcimator

Work-in-Process (WIP) Calculator

Calculate WIP inventory value across production stages using Little's Law and estimate carrying costs.

Inputs

units/day
days
$
%

Results

WIP Inventory Value

$25,000.00

≈ 13 gaming PCs

WIP Units1,000 units
Annual Carrying Cost$6,250.00
Monthly Carrying Cost$520.83
WIP Turns per Year73
Days of Inventory5 days
Savings if Lead Time Halved$12,500.00
How to Use This Calculator
  1. Enter the average throughput rate in units per hour.
  2. Input the average lead time through the system in hours (Little's Law: WIP = throughput × lead time).
  3. Set the number of active workstations and WIP storage locations.
  4. Review the estimated WIP inventory count and its value at average unit cost.
  5. Reduce lead time or WIP limits to cut inventory cost and expose flow constraints.

How the result changes with Daily Throughput

Daily ThroughputWIP Inventory Value
100,001$12,500,125.00
350,001$43,750,125.00
650,000$81,250,000.00
900,000$112,500,000.00

What each input means

Daily Throughput
Average number of finished units produced per day.
Production Lead Time
Average time a unit spends in production from start to finish.
Average Cost per Unit
Average accumulated cost per WIP unit (material + labor + overhead to midpoint).
Annual Carrying Cost
Annual inventory carrying cost as percentage of value (typically 20-30%).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Daily Throughput = 200, Production Lead Time = 5, Average Cost per Unit = 25, Annual Carrying Cost = 25 = 4 input(s) provided
  2. Calculate WIP Inventory Value
    WIP Inventory Value
    25000 = $25,000
  3. Calculate WIP Units
    WIP Units
    1000 = 1000
  4. Calculate Annual Carrying Cost
    Annual Carrying Cost
    6250 = $6,250

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