Enter the time for each task on your line and a target cycle time (or derive it from your required output). The tool computes total work content, the theoretical minimum number of workstations, line efficiency, balance delay, and flags any task that is too long to fit a single station.
Assembly line balancing assigns work tasks to a sequence of stations so that each station's workload is as close to the cycle time as possible, with the fewest stations and the least idle time. This calculator takes your task times and a target cycle time (set directly or derived from required output) and returns the total work content, theoretical minimum number of stations, line efficiency, and balance delay, while flagging any task too long to fit a single station.
Cycle time (C) is the maximum time a unit may spend at any one station โ it sets the pace of the line. To meet a customer requirement you usually set the cycle time at or below the takt time, where takt time = available production time per period รท units required per period. For example, 27,000 seconds of available time and 450 units required gives a takt of 60 s/unit.
Total work content (ฮฃt) is the sum of all task times for one unit. The number of units the line can produce per hour is 3,600 รท cycle time (in seconds).
The fewest stations the line could possibly need is N_min = โฮฃt / Cโ โ the total work content divided by the cycle time, rounded up. You can never do better than this, because no station may exceed the cycle time. In practice you often need more than N_min stations because task precedence constraints and the fact that tasks are indivisible prevent a perfect split. The gap between N_min and the stations you actually use shows up as balance delay.
Line efficiency = ฮฃt / (N ร C), where N is the actual number of stations. It is the fraction of total available station-time that is actually doing value-added work. Balance delay (or balancing loss) = 1 โ efficiency, the fraction of station-time that sits idle waiting for the cycle to advance.
A well-balanced manual line typically runs above 85% efficiency. Lower efficiency means some stations finish early and wait โ money spent on labor and equipment that produces nothing. Raising efficiency usually means re-distributing tasks, splitting a long task, combining short ones, or reducing the number of stations.
If any single task takes longer than the cycle time, the line is infeasible as designed โ that task alone cannot keep pace, so it becomes a hard bottleneck no matter how you arrange the others. Your options are: split the task into smaller sub-tasks across stations, run that operation in parallel (duplicate stations), invest in a faster method or machine, or relax the cycle time (accept lower output). This calculator flags this condition automatically by comparing the longest task time to the cycle time. The longest task time is the absolute floor on achievable cycle time for a single-path line.
Line balancing is the process of assigning the tasks needed to make a product to a sequence of workstations so that each station has roughly equal work, the line meets its required output (cycle time), the number of stations is minimized, and idle time (balance delay) is as low as possible โ all while respecting the order in which tasks must be performed (precedence constraints).
Takt time is the demand-driven pace: available production time divided by customer demand for that period. Cycle time is the actual pace the line runs at โ the time a unit spends at the slowest station. To meet demand you design the line so its cycle time is at or below the takt time. Running faster than takt overproduces; running slower fails to meet demand.
Line efficiency = total work content รท (number of stations ร cycle time). It expresses how much of the available station-time is doing real work. Multiply by 100 for a percentage. Balance delay, the idle fraction, is simply 1 minus the efficiency.
It is the total work content divided by the cycle time, rounded up to the next whole number: โฮฃt / Cโ. This is a lower bound โ you can never use fewer stations than this. Real lines often need a few more because of precedence constraints and indivisible tasks.
Then the line cannot meet that cycle time, because that task by itself exceeds the allowed time per station. You must split the task, parallelize it across duplicate stations, speed it up, or increase the cycle time. The longest single task sets the minimum possible cycle time for a single-path line.