Paul Ducey
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✓ Free · MIT License Manufacturing Healthcare Operations

Capacity Planner

Before you add labor or equipment, run the math. The bottleneck is rarely where you think it is. Machine, labor, and WIP/material capacity checked station by station against takt time, with what-if scenarios modeled before you spend a dollar.

Problems This Solves

Four ways capacity decisions go wrong

Expansion that didn't solve the real constraint
Added a machine to a non-bottleneck step. Throughput didn't change. The real constraint was two steps upstream and nobody ran the math.
Labor added to the wrong station
Labor hours were tight everywhere, so capacity was spread evenly. The bottleneck needed all of it, not a fraction of it.
Equipment purchased before checking material flow
A new machine was ordered. Six months later it sat starved, because material never arrived at the rate it could run. WIP and material capacity was never part of the model.
No model for volume increase scenarios
Sales promises a 20% volume ramp. Nobody can say which constraint breaks first, or at what volume. The answer should take minutes, not weeks.

Three Dimensions

Every capacity model needs all three

Most capacity analyses look at only one dimension. A cell with plenty of machine time can still be constrained by labor, or by material that doesn't arrive. The skill addresses all three before it says which one limits the process.

⚙️
Dimension 1
Machine Capacity
Available time × OEE ÷ Ideal cycle time
Machine time adjusted for OEE to get realistic productive time, then divided by the ideal cycle time. Quoted cycle times are often theoretical, so nameplate capacity overstates real capacity whenever OEE is below 100%. With the observed cycle time, speed loss is counted twice.
👷
Dimension 2
Labor Capacity
Available time × Operators ÷ Labor content per unit
The work content at each station compared with takt time. Often independent of machine capacity: a station can be machine-bound, labor-bound or both, and each needs a different fix.
📦
Dimension 3
WIP and Material Capacity
Buffers, staging and replenishment vs. consumption
The rate material can move through the process given storage buffers, staging areas and replenishment lead times. A material shortage often looks like a labor or machine shortage: the machine is starved or blocked, not incapable.
OEE-adjusted machine capacity

Machines don't run at 100%. A machine available 8 hours per day with a 72% OEE has 5.76 productive hours, not 8. Where OEE data exists, the skill shows the theoretical and the OEE-adjusted analysis side by side. Using nameplate capacity makes the machine look 39% more capable than it is in this example.

Bottleneck

Only one station is the real constraint

System capacity equals the bottleneck's capacity. Adding capacity anywhere else won't increase output. This is the most common and most expensive mistake in capacity planning.

How the skill identifies the bottleneck

For each station, the skill calculates the capacity ratio: station cycle time ÷ takt time. Above 1.00 the station cannot meet takt, 0.85 to 1.00 is at risk, and below 0.85 there is buffer. The station with the highest ratio is the bottleneck, and the skill says whether machine, labor or WIP/material limits it. Cycle times are never averaged across stations.

What-If Scenarios

Which station breaks first when volume rises?

For each scenario the skill recalculates takt time and station loading from scratch, not as a percentage on top of the baseline. The first station whose ratio passes 1.00 shows what breaks and the action it requires.

Example: Assembly Cell, 3 Volume Scenarios

Available time: 26,400 s per day (one 8-hour shift less breaks) · 4 stations, 1 operator each · Illustrative numbers.

Station (cycle time) Current: 200/day, takt 132 s +10%: 220/day, takt 120 s +20%: 240/day, takt 110 s Breaks at
1 Prep (95 s, labor) 0.72 · OK 0.79 · OK 0.86 · At risk +39% volume
2 Press (108 s, machine) 0.82 · OK 0.90 · At risk 0.98 · At risk +22% volume
3 Assembly (118 s, labor) 0.89 · At risk 0.98 · At risk 1.07 · OVER +12% volume ← bottleneck
4 Test (80 s, machine) 0.61 · OK 0.67 · OK 0.73 · OK +65% volume
Reading this table

Station 3 is already at 0.89 at current volume, and it is labor-bound: 118 s of work against a 104 s machine cycle. A 12% volume increase puts it over takt before any other station. The first move is to rebalance the labor content at Station 3, not to add an operator or a machine. Station 2 is the next constraint, at 244 units per day.

Capacity Gap Analysis

Required vs. available, for every dimension

The same cell at +10% volume (220 units per day).

Dimension Required Available Gap Recommended Action
Labor (Station 3) 118 s/unit × 220/day = 25,960 s 26,400 s (1 operator × one shift) +440 s At risk (ratio 0.98). Rebalance work off Station 3 before adding anyone
Machine (Station 2) 108 s/unit × 220/day = 23,760 s 26,400 s +2,640 s At risk (ratio 0.90). Next constraint after Station 3
WIP / material [NEEDS GEMBA] [NEEDS GEMBA] [NEEDS GEMBA] Not provided, so assumed not the constraint [ASSUMED]. Check for starved or blocked stations on the floor

Examples

Manufacturing and clinical throughput planning

🏭 Manufacturing
🏥 Healthcare

Assembly cell capacity model: 4 stations, 1 operator per station, 1 shift (26,400 s available after breaks). What-if at +10% and +20% volume. Station 3 identified as the bottleneck (labor-bound); it breaks at +12%.

Cell: Final Assembly
Stations: 4 · Operators: 1 per station · Shifts: 1 (26,400 s available)
Takt at current volume (200/day): 132 s

Bottleneck at current volume: Station 3, labor-bound (118 s), ratio 0.89, At risk
System capacity: 223 units/day (+12%)
Breaks at: +12% volume (about +24 units/day)
Recommended action: rebalance labor content at Station 3. Station 2 is the next constraint at 244 units/day
[NEEDS GEMBA: confirm Station 3 labor content with a timed observation; WIP and material not provided]

Outpatient clinic throughput planning. The skill adapts vocabulary: "units" becomes "patient visits," "machine capacity" becomes "room capacity" (exam rooms × clinic hours ÷ average visit time, adjusted for how much of that time rooms are actually in use). Labor capacity models provider and MA time separately.

Healthcare note

Room capacity can be the binding constraint in clinic throughput planning, not provider hours, so the skill checks both. Adding provider time without adding exam rooms shifts the bottleneck rather than relieving it. The skill models all three dimensions before any staffing or facility decision.

What you get

A real run on the sample data

Unedited output. The sample message at the top went to Claude Sonnet 4.6 (an earlier-generation model, so a newer one may word things differently) with this skill pasted in, the same way the steps below show, on September 29, 2026. Scroll inside the frame to read the whole reply.

Capacity Planner: the full reply from a real run on the sample data, ending with what the skill did, what still needs a human, and one next step.

Open the full image

Installation

Describe your cell. Get the capacity model.

1
Copy the skill. Open capacity-planner.md, select all the text and copy it.
2
Paste it into Claude. In claude.ai, start a new chat and paste it as your first message, or paste it into a Project's instructions so it's there every time. The free plan works, and free accounts can keep up to five Projects.
3
Say what's in front of you, in your own words, with any data you have (leave out names). Say "model capacity for [cell or department name]" and describe operators, machines, shift hours, OEE, and target volume, or paste a layout or spreadsheet. Add "just draft it" to skip the questions and get the whole deliverable now. Paste numbers, not a picture of a chart: language models can misread figures. If your plan lets you switch on Code execution in Claude's settings, turn it on so the arithmetic is run, not estimated, and spot-check any number you plan to act on.
4
See a finished example first (optional): the worked examples are in the download, in the resources/examples folder.

Related Skills

Capacity planning connects to VSM and OEE

A VSM shows which steps have the most inventory and longest lead times. Capacity planning shows why. If machine capacity is the binding constraint, OEE analysis explains where the capacity is being lost.