Free tool
Line balancing calculator
Line balancing is spreading work across the stations of a line so that each station's workload is close to takt time and to the others. Line efficiency shows how evenly the work is spread, balance delay shows how much station time is lost to waiting, and total work divided by takt gives the fewest stations the line needs.
Line balancing formula: line efficiency and balance delay
Line efficiencyequalsTotal work content divided by Number of stations × Cycle time
Balance delayequals1 − Line efficiency
Minimum stationsequalsTotal work content divided by Takt time, rounded up
Line targetequalsAvailable time divided by Cycle time
Pre-filled with the worked example. A station's time is all the work one operator does on one unit there.
Line efficiency
75.0%
270 s of work spread over 6 stations at a 60 s cycle.
Balance delay
25.0%
Share of station time spent idle
Idle time per cycle
90 s
Across all stations
Minimum stations
5
Total work ÷ takt, rounded up
Bottleneck
Station 3
60 s (within takt)
Prefer a spreadsheet? Download the Excel version: the free operator staffing calculator checks a station plan of up to 60 elements and 20 stations and gives the balance efficiency and balance delay.
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How to calculate it
How to balance a line: station times against takt
Station times are the work one operator does on one unit at each station, measured or taken from time studies. Add them up for the total work content.
Takt time is the pace demand requires. If you don't have it yet, the takt time calculator works it out from shift time and demand.
The slowest station is the bottleneck. If it is within takt, the line runs at takt and every other station waits part of each cycle. If it is over takt, it sets the pace and the line falls short of demand. Drawing the station times as a Yamazumi chart makes both cases easy to see.
Line efficiency calculation example
Illustrative numbers, not a benchmarkA line with a takt time of 60 seconds and six stations taking 50, 40, 60, 35, 45 and 40 seconds per unit.
Step 1
Total work content = 50 + 40 + 60 + 35 + 45 + 40 = 270 s.Step 2
The slowest station (station 3) takes 60 s, equal to takt, so the cycle time is 60 s.Step 3
Line efficiency = 270 ÷ (6 × 60) = 270 ÷ 360 = 75%. Balance delay = 25%, or 90 s of idle time per cycle.Step 4
Minimum stations = 270 ÷ 60 = 4.5, rounded up to 5.Step 5
Line target = 27,000 s of available time (a 450-minute shift) ÷ 60 s = 450 units a shift, 60 an hour.
Line efficiency means two things
Plants use the words for two different measures. Say which one you mean before you compare numbers with another plant.
| Measure | Formula | It tells you |
|---|---|---|
| Balance efficiency | Total work content ÷ (stations × cycle time) | How evenly the work is spread. The best the layout can do |
| Output efficiency | Units made ÷ units the line should have made | What happened in the shift, including stops, absence and shortages |
Illustrative. The line above is 75% balanced. In a shift where it was stopped for 45 minutes it would still be 75% balanced and make fewer than its 450 units. Balance efficiency does not move; output efficiency does. Track both. For the stops, use the OEE calculator.
How to rebalance a line
- Fix the pace. Work out takt time. No station may take more than that.
- Break the work into elements. Time each one, from a time study, and write down which must come before which.
- Find the fewest stations. Total work content ÷ takt, rounded up.
- Fill stations in order. Give each station elements until the next one would push it past takt. When two elements could go next, take the one with the larger positional weight: its own time plus the time of every element that follows it. Helgeson and Birnie described this ranked positional weight rule in 1961. It is a rule of thumb and does not always find the best answer.
- Recalculate and walk it. Put the new station times in the calculator, then check on the floor that the move is safe and that quality checks still happen. Draw it as a Yamazumi chart and keep the result on the standard work combination table.
To turn the result into a head count, see how many operators a line needs.
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<iframe src="https://www.theleansuite.com/tools/line-balancing-calculator/embed" title="Line balancing calculator by LeanSuite" width="100%" height="1350" style="border:0;max-width:1000px" loading="lazy" allow="clipboard-write"></iframe>
<p style="font:13px/1.4 sans-serif"><a href="https://www.theleansuite.com/tools/line-balancing-calculator">Line balancing calculator</a> by LeanSuite</p>How LeanSuite helps
From a video of your line, LeanSuite's Line Balancing charts each operator's work elements against takt, and lets you move elements between stations in a simulation to see the new balance before changing the line.
See Line BalancingFAQ
Line balancing calculator: common questions
Add up the work time at every station to get the total work content, then divide it by the number of stations times the cycle time. For example, 270 seconds of work over 6 stations at a 60 second cycle is 270 / 360 = 75% efficient.
Balance delay is the share of station time lost to waiting because the work is not spread evenly. It is 1 minus line efficiency, or total idle time divided by the number of stations times the cycle time. For example, a line at 75% efficiency has a balance delay of 25%.
Divide the total work content by takt time and round up to the next whole number. With 270 seconds of work and a 60 second takt, 270 / 60 = 4.5, so the line needs at least 5 stations. Reaching that minimum depends on whether the tasks can actually be split and moved between stations.
Use the pace the line really runs at. When every station is within takt, the line is paced to takt, so efficiency is measured against takt. When a station is slower than takt, that station sets the pace, so efficiency is measured against its time and the line will not meet demand until it is fixed. This calculator applies that rule automatically.
A Yamazumi chart is a stacked bar chart of the work content at each station, drawn against a line for takt time. It shows at a glance which stations are overloaded or underused, and it is the usual tool for seeing and redistributing work when balancing a line.
Two measures share the name. Balance efficiency, which this calculator gives, is total work content divided by the number of stations times the cycle time: how evenly the work is spread. Output efficiency is the units actually made divided by the units the line was meant to make, or the minutes of work earned divided by the minutes paid. A line can be well balanced and still miss its output because of stops and absence.
Divide the available time by the cycle time the line runs at. At a 60 second cycle the line makes 3,600 / 60 = 60 units an hour, and 27,000 seconds of available time make 450 units a shift. Use takt time as the cycle time to get the output the customer needs; use the slowest station if that is longer.
In theory, yes: efficiency is 100% when every station's work time equals the cycle time. In practice, tasks cannot always be split, some must happen in a set order, and operators vary, so most lines keep some idle time.
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