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VSM guide / Lean tools / Line balancing calculator
Line balancing calculator
Balance work across operators against takt: list the tasks and their times, and see how many operators you need, each operator's load on a yamazumi chart, the balance efficiency and a U-shaped cell layout. Free, no sign-up.
How line balancing works
Total work content
Add up the operator work per part across the tasks: manual work and walking. Machine time that runs on its own doesn't count, unless the operator has to wait for it.
Operators needed
Total work ÷ takt time gives the theoretical number. Round up for the real one, and plan to remove work until the last operator is fully loaded or not needed.
Balance to takt
Give each operator tasks in flow order until they reach takt (or a fill target, like 95%, to leave room for variation). The yamazumi chart shows each operator's stack against the takt line.
Balance efficiency
Total work ÷ (operators × takt). Above 85% is good. A big gap on the last operator is a kaizen target: remove that much waste and one person is freed for other work.
From a balanced line to a cell
Continuous flow puts the balanced steps next to each other, usually in a U-shape, so parts move one at a time and the inventory between the steps disappears. The first and last stations sit side by side, so one operator can handle both, and walking is short.
In the VSM Studio builder, open Cell design on a process box or a "Flow" kaizen burst: it takes each step's work content from its time study, balances it to takt, and Merge into one cell combines the steps on the map and removes the WIP between them.
Questions
What is line balancing?
Distributing the work of a line across operators so each one has close to takt time of work, no one is overloaded and the line meets customer demand with the fewest people.
How do I calculate the number of operators?
Divide the total operator work content per part by takt time, then round up. Example: 112 s of work at a 60 s takt needs 1.87, so 2 operators.
What is a yamazumi chart?
A stacked bar chart (yamazumi means "stack up" in Japanese) showing each operator's work elements piled up against the takt line. It makes overloaded and underloaded operators obvious.
Why fill operators to less than 100% of takt?
Real work varies from cycle to cycle. Planning each operator at around 90–95% of takt leaves room for that variation so the line still keeps pace.