Last Updated on 13 September 2023
Takt time is a key element of Just In Time and the first metric that you’ll calculate when making a value stream map. This makes it a key part of making lean operations. It is a German word for precise interval of time like a metronome, and is the ‘beat of production’. It is the ‘beat’ that you need to produce your product to in order to meet customer needs. If you set a metronome to tick at the beat, you’d need to produce one good unit of output for each ‘tick’ you hear.
Takt time is the time you have to produce one good unit of output in order to meet customer demand
Why do we use it?
By measuring this time you know what speed your processes need to be working at to meet customer demand. If you manage to get all of your processes to work to ‘beat’, you’ll be working efficiently as you’ll be working just fast enough to meet demand with with no overproduction.
Bottlenecks are caused by processes working slower than the process before them. If you manage to get all your processes working to the takt time, you will remove all of the bottlenecks, as all your processes will be working at the same speed.
One piece flow
The aim is to achieve ‘one piece flow’. This is where one item starts being produced and flows through all your processes without any waiting at any of the steps. If you align all of your processes to the beat, you can achieve one piece flow where everything flows through smoothly. This will keep your processes at exactly the right speed to meet customer demand whilst minimizing related wastes.
How do you calculate it?
The formula is:
Takt time = Time available per shift / number of good units to produce in the shift to meet demand
It is made up of two parts: time available per shift and number of good units to produce.
Time available per shift
The time available is the time your process could theoretically be producing units. The time available is therefore:
Time available per shift = total shift length – breaks – downtime
For what is acceptable to remove:
|Meetings||Waiting for jobs to come|
|Breaks and lunch|
Number of good units
The takt time is a theoretical number, so you will usually assume all units produced will be good, so we will generally assume zero defects. In reality there will be defects, but we can worry about that when we’re calculating cycle time.
We therefore concentrate on what the customers want. If we’ve received orders for 1,000 units this week, and there are 5 working days each with 2 shifts, our number of good units needed per shift becomes:
Number of good units per shift = weekly demand / number of shifts in week = 1,000 / (5 x 2) = 100.
Takt time vs Cycle time
The metric is rarely any use by itself, unless you are going to set up a giant metronome in your work space. To know how you are performing, you need to compare it to your cycle time, which is how long it is actually taking you to produce the units.
You can use operator balance charts to compare the two times for your processes:
If the bar is below the line, you’re working faster than your process requires, but if the bar is above you’re slower than needed.
Working too slow
If any one of your processes has a cycle time longer than your takt time, it won’t be able to create your product fast enough to meet the demand from your customers. You’ll miss deadlines and lose sales, harming your top line and upsetting your customer.
You need to get these processes faster to meet the required speed, either by adding resources or removing waste from the process.
If you can’t improve upon your cycle times, it is possible to ‘slow down’ your takt time by changing the only part of the formula under your control – the time available. By reducing the number of meetings or adding overtime, you can increase the time available, making the your target easier to achieve.
Working too fast
You may think that the ideal is working much faster than needed, as you’ll easily make demand? This unfortunately comes with its own issues, primarily creating costly wastes.
If some of your processes are faster, they will end up waiting for the processes before them, creating waiting waste. If the processes before can keep up, there will be bottlenecks at the first process that can’t, where inventory will stack up. This will lead to inventory waste (as the earlier processes will be making unusable WIP that the later stages can’t use).
If all of your processes are faster, this will create overproduction waste, as you will be producing more finished goods than is needed, and are likely using more production resources than needed. As you can see, working faster causes almost as much of an issue as working slower.
Perfect balance for improved flow
Rather than working too fast or too slow, what you actually want to aim for is all processes working at takt time, as this will let you produce everything you need at the rate you need it. You won’t be wasting resources with processes waiting for others or over staffing. There will be the least amount of resources needed to run your organization.
This makes it incredibly important for achieving lean, as it controls the speed that you need for every part of every process.
You may find that takt time doesn’t work for all processes, as customer orders are usually in standard ‘batches’, to fill a box or shipping container. Often past a certain point (especially if you include shipping in your analysis), you’re measuring the wrong thing.
Pitch time is the equivalent metric but for a batch, such as to include a box of goods. A department such as shipping where one unit of output is the batch will need to work to the pitch time to meet customer demands.
Pitch time = takt time x number of items per batch.