- Enter cycle times for each station on your production line.
- Enter takt time (customer demand pace).
- Click Calculate to see line balance efficiency and bottleneck station.
The Line Efficiency Formula
Understanding Line Efficiency
Line efficiency (line balance efficiency) measures how evenly work is distributed across all stations in a production line. A perfectly balanced line has every station taking exactly the same time — 100% efficiency. In reality, work elements have different durations, so some stations finish faster than others and wait idle.
This idle time is pure waste: you are paying labor to stand still. The station with the longest cycle time (the bottleneck) sets the pace for the entire line, and every other station waits for it.
1.2 min
1.5 min
0.9 min
1.1 min
1.4 min
Real-World Example
A 5-station assembly line has cycle times of 1.2, 1.5, 0.9, 1.1, and 1.4 minutes.
Bottleneck CT = 1.5 min (Station 2)
Efficiency = 6.1 / (5 x 1.5) = 6.1 / 7.5 = 81.3%
Idle time per cycle = 7.5 - 6.1 = 1.4 minutes wasted
Station 3 (0.9 min) has the most idle time: 0.6 min every cycle. Consider moving work elements from Station 2 to Station 3.
Line Efficiency Benchmarks
| Efficiency | Rating | What It Means |
|---|---|---|
| 90%+ | Excellent | Very well balanced. Minimal idle time. |
| 85-90% | Good | Well-balanced line with small gaps. |
| 70-85% | Average | Notable imbalance. Improvement opportunity. |
| Below 70% | Poor | Major imbalance. Significant waste in idle time. |
How to Improve Line Balance
✅ Good Line Balancing
- All stations within 10% of each other
- Bottleneck station at or near takt time
- Work elements grouped logically
- Regular re-balancing as demand changes
❌ Common Mistakes
- Ignoring precedence constraints
- Balancing to the fastest operator
- Never re-timing after initial setup
- Adding stations instead of redistributing work
🎯 Key Takeaway
Line efficiency directly impacts labor cost per unit. A line at 75% efficiency means 25% of your labor cost is paying for idle time. Measure every station, identify the bottleneck, redistribute work, and aim for 85%+ balance. Small improvements in balance compound into significant cost savings.
Frequently Asked Questions
What is line efficiency?
Line efficiency (also called line balance efficiency) measures how evenly work is distributed across stations in a production line. 100% means every station takes exactly the same time. Low efficiency means some stations are idle while the bottleneck works.
How is line efficiency calculated?
Line Efficiency = Sum of All Station Cycle Times / (Number of Stations x Bottleneck Cycle Time) x 100. The bottleneck is the station with the longest cycle time.
What is a good line efficiency?
85% or above is considered well-balanced. Most production lines operate between 75-90%. Below 70% indicates significant imbalance and idle time waste.
What is the difference between line efficiency and OEE?
Line efficiency measures work distribution balance across stations. OEE measures equipment effectiveness (availability x performance x quality). A line can have high OEE but poor balance, or vice versa.
How do you improve line balance?
Redistribute work elements from overloaded stations to underloaded ones. Split tasks, combine tasks, add parallel stations at the bottleneck, or adjust the number of operators. The goal is to match each station to takt time.
What is idle time and why does it matter?
Idle time is the gap between a station's cycle time and the bottleneck cycle time. Every station except the bottleneck has idle time. This represents paid labor not producing value. Total idle time = (Number of Stations x Bottleneck CT) minus Sum of all CTs.
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