BIZOMAT Tools · Operations
Capacity Check
How much can you realistically produce?
Calculates practical capacity from available hours, parallel stations, cycle time and efficiency, and compares it with demand.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Available hours / period | hr | Scheduled hours in the period at the constraint |
| Machines / parallel stations | stations | Parallel machines or stations doing the same work |
| Cycle time / unit | min | Measured cycle time per unit at the constraint |
| Realistic efficiency | % | Demonstrated efficiency (or OEE) at the constraint |
| Demand / period | units | Orders or forecast for the same period |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Available hours / period
- What it is
- The scheduled working hours of one machine or station at the constraint during the period, such as shift hours across the month.
- Units and format
- Enter a number in hr: hours. The form accepts 0 hr or more.
- Example
- The form opens with 160 hr as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Capacity rises in proportion to available hours.
- Get it right
- Give hours for one station; the tool multiplies by the number of stations. Deduct planned shutdowns.
What this means: Machines / parallel stations
- What it is
- How many identical machines or stations do the same operation side by side, so their hours add together.
- Units and format
- Enter a number in stations: stations. The form accepts 1 stations or more. Use a whole number.
- Example
- The form opens with 2 stations as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Capacity rises in proportion to the number of stations.
- Get it right
- Count only stations that can run this product at the same cycle time.
What this means: Cycle time / unit
- What it is
- The time one station takes to complete one unit at the constraint, measured from the start of one unit to the start of the next.
- Units and format
- Enter a number in min: minutes. The form accepts 0.01 min or more.
- Example
- The form opens with 4 min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Capacity falls in proportion as cycle time grows.
- Get it right
- Enter minutes, not seconds: 45 seconds is 0.75 minutes.
What this means: Realistic efficiency
- What it is
- The share of scheduled time that actually produces good output after breakdowns, changeovers, slow running and small stops, from recent records or OEE.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 1% to 100%.
- Example
- The form opens with 85% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Capacity rises in proportion to efficiency.
- Get it right
- Use a demonstrated figure, not a target. If changeovers are deducted from hours, do not count them here too.
What this means: Demand / period
- What it is
- The number of units ordered or forecast for the same period as the available hours.
- Units and format
- Enter a number in units: a count of units. The form accepts 0 units or more.
- Example
- The form opens with 3500 units as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Utilisation rises in proportion to demand; capacity does not change.
- Get it right
- Match the period: monthly demand against weekly hours gives a wrong utilisation.
Method and formulas
- Capacity = hours × 60 × stations × efficiency ÷ cycle time (minutes)
- Utilisation = demand ÷ capacity
- Comfortable to 85%, tight to 100%
Limitations
- Single product and constant cycle time
- Changeovers must be inside efficiency or deducted from hours
Typical uses
- Checking whether a forecast can be made
- Deciding on overtime, extra shifts or outsourcing
Who it is for
- Production planners
- Operations managers
What you get
- AVAILABLE, TIGHT or SHORTFALL
- Practical capacity, utilisation and buffer
Interpreting the result
- Utilisation above 85% leaves little room for breakdowns and variation
References
- Hopp W. J. and Spearman M. L., Factory Physics (Waveland Press) on utilisation and variability
Learn the Concepts Behind This Tool
These BIZOMAT Library readings explain the method this tool uses, with worked examples.
Method explained here · BIZOMAT original book
Building a demand forecast from its drivers
In Demand and Benefit Forecasts by the Numbers
What it covers: The plant's 25.32m cans split into customers, runs and run sizes, converted to 3,680 line hours (92.0%) and contribution per hour, and eight 'new' customers who were not new.
Method explained here · BIZOMAT original book
Working back from the gap to its causes
In Outcome-First Projects by the Numbers
What it covers: A Pareto of 412 failed deliveries and a capacity check on effective rates: ironers and dispatch cause 83%, the ironers are 20% short on peak days, and the washers are not the constraint.
Method explained here · BIZOMAT original book
Loading several machines
In Shop Floor Optimisation by the Numbers
What it covers: Load jobs onto three or more identical machines: the two lower bounds, the longest-first rule and its guarantee, its worst case, jobs that arrive during the day, and a capacity check over the week.
BIZOMAT tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.