Short answer
A Yamazumi chart is a standard Lean line-balancing tool: one bar per workstation, with the tasks performed there stacked on top of each other, plus a horizontal customer-takt-time line as the target. A bar that rises above the takt line marks a bottleneck — a workstation that can't keep up with the pace the customer requires. This generator is free, with no limits and no registration: you enter the data, and immediately see the chart and an automatically calculated takt time.
What a Yamazumi chart is
Yamazumi (Japanese: 山積み) literally means "piling up" — and that's exactly what this chart shows: tasks piled one on top of another in a single bar, separate for each workstation. It's one of the core Lean Manufacturing tools for line balancing — distributing work across workstations so that none of them is either overloaded or underloaded relative to the pace the customer requires.
Unlike a regular bar chart, which lines up the times of individual tasks or steps side by side, Yamazumi groups them by the workstation where they're actually performed and sums them into one bar. That means a single glance shows not only which tasks take the longest, but — more importantly — which workstation has the most work overall.
Why this tool exists
A Yamazumi chart is usually drawn at a Kaizen workshop — on a whiteboard, sticky notes or in Excel. That works, but it has a downside: when the data changes (you move a task between workstations, test a different work split), everything has to be redrawn by hand, and the takt-time line is rarely recalculated on the fly.
I built this generator for the same reason I built FlowMapper AI — my VSM mapping tool: to take the tedious drawing and calculating on myself and leave the team time for what actually matters — the discussion about where to move work and why a given workstation is overloaded. You enter the data, and the chart and status (within takt / exceeding takt) calculate themselves, live.
What the tool does
- Grouping tasks into workstations — you enter any number of tasks with a workstation name, the tool sums them into bars automatically.
- Automatic stacked chart — colored segments per task, with a readable time value inside each segment and a total above the bar.
- Customer takt time as a target line — enter it directly, or calculate it automatically from available working time and customer demand.
- Instant status — a clear message on how many workstations exceed takt time (bottleneck) and how many are within the norm.
- Print and PDF export — directly from the browser, ready to print for a Kaizen workshop.
- Data stays local, no cloud — the data you enter is saved in the browser (localStorage) and never sent anywhere.
How customer takt time is calculated
This is the pace at which the customer "takes" one unit or one case. If the sum of task times at a given workstation (the height of the Yamazumi bar) exceeds takt time, that workstation can't keep up with demand under normal conditions — the tool flags it with a red warning in the summary. It's worth distinguishing takt time from cycle time: takt time is the required pace (derived from demand), while cycle time is the actual, measured execution time — comparing the two on the Yamazumi chart is exactly what reveals where the problem is.
How to read a Yamazumi chart
Open the tool
Below is the working application — you can enter your process data right away. The demo version comes pre-filled with sample data, which you can freely overwrite or clear.
How to get started (4 steps)
Collect the data
For each workstation, record the tasks performed there and their duration — ideally measured on site, not from a system standard.
Enter the data into the tool
For each task, add a row: workstation name, task name, time in seconds. The tool automatically groups tasks into workstations.
Set the customer's takt time
Enter takt time directly, or calculate it from available working time and customer demand.
Read the result and balance the line
Workstations above the takt line are bottlenecks — move work off them onto workstations with spare capacity, or shorten the task itself.
Frequently asked questions
What is a Yamazumi chart?
A Lean chart showing the cumulative workload of every workstation — one bar per workstation, with the tasks performed there stacked on top of each other.
How is Yamazumi different from a regular bar chart of times?
A regular chart shows task times side by side. Yamazumi groups them by workstation and sums them into one bar, showing the real workload of each workstation, not just individual task times.
How do you calculate customer takt time?
Takt time = available working time ÷ customer demand in the same period. It's the pace at which you need to finish one unit to keep up with orders.
What should you do when a workstation exceeds takt time?
That's a bottleneck — move some work to a workstation with spare capacity (rebalancing), shorten the task, or add a resource at that workstation.
Is my data stored in the cloud?
No — the data stays locally in the browser (localStorage), nothing is sent to a server.
Is the generator free?
Yes, fully free with no limit on the number of workstations or tasks, and no registration.