Assembly Line Balancing Calculator
Line balance efficiency from station times and takt time — bottleneck station, balance delay, idle time per cycle, theoretical minimum stations, output per shift and which stations to rebalance.
How it works
Efficiency = Σ station times ÷ (stations × bottleneck time); balance delay = 1 − efficiency; minimum stations = ⌈Σ times ÷ takt⌉; output = available time ÷ bottleneck time; smoothness = √Σ(max − tᵢ)²
On a paced line every station waits for the slowest one, so the line’s cycle time is the bottleneck’s and every second the other stations finish early is idle labour. Balance efficiency compares the work actually performed each cycle with the operator-time consumed; 85–95% is good for manual assembly. Dividing total work content by takt gives the theoretical minimum number of stations, and the gap to the number actually used is the price of indivisible tasks and precedence constraints. Rebalancing moves work elements from the bottleneck to under-loaded neighbours until all stations sit just under takt; if the total still needs fewer stations than you have, combine stations rather than leaving several half-empty.
Worked example
Six stations of 52, 45, 58, 40, 55 and 38 s (288 s total) against a 60 s takt: station 3 paces the line at 58 s, efficiency 288 ÷ (6 × 58) = 82.8%, 60 operator-seconds idle per cycle. Five stations could carry 288 s at 57.6 s each, freeing one operator.
Frequently asked questions
Efficiency vs the bottleneck or vs takt?
Versus the bottleneck measures how well the stations are balanced against each other; versus takt shows how much of the customer-paced time is used. Report both — a well-balanced line can still be far slower than takt.
How do precedence constraints affect this?
Some tasks cannot move upstream of their predecessors, so the practical balance is often a few points below the arithmetic ideal; heuristics like ranked positional weight help assign elements.
Related calculators
Operations planning estimate based on the figures entered; validate against measured shop-floor data before changing staffing, equipment or customer commitments.