Workforce requirements planning: How to calculate optimal staffing levels
Knowledge | August 20. 2026
A company can only perform effectively and operate economically if it has the right number of employees with the right qualifications for its current operations and future direction. Workforce requirements planning is crucial to operational performance, achieving KPIs and ensuring a company’s future viability. This remains a challenge: companies in Germany are facing a shortage of skilled workers, while demographic change means that many employees are also retiring. Despite planned measures to make working hours more flexible and other proposed reforms, filling these gaps will remain difficult. At the same time, it is foreseeable that AI will fundamentally change the world of work and business models. However, exactly what these changes will look like and what they will mean for workforce scheduling in individual cases remains completely open. Only one thing is certain: reliable workforce requirements planning will continue to depend on a sound basis for planning – namely, the most accurate possible data on past activities.
What is workforce requirements planning and why is it crucial?
Workforce requirements planning essentially has two tasks. The first is to calculate staffing requirements, i.e. determine how many employees with which qualifications a company or organisation needs in order to complete upcoming tasks effectively. The second is to forecast how many employees with which qualifications the company will need to recruit in the future. This may be to replace employees who leave, enable business growth or recruit the right employees for a future corporate strategy.
Workforce requirements planning is therefore an important factor in competitiveness because it helps ensure that the workforce is structured so that this resource can be deployed as efficiently as possible. In addition, the data collected and models created as part of workforce scheduling provide the data basis for strategic workforce planning. They make it possible to identify requirements and recognise and develop the potential of the existing workforce. Both are prerequisites for future-proof workforce planning.
Quantitative vs qualitative staffing requirements – the difference
A distinction is made between quantitative and qualitative staffing requirements. Quantitative requirements refer to the number of employees needed, including reserves, for the forecast workload. Qualitative requirements, by contrast, describe the specific prerequisites and qualifications required to provide the services. A simple example: if a heating system in a residential building needs to be connected to the power supply, a basic certified training course may be sufficient. If work needs to be carried out on switchgear cabinets or distribution boards in the same building, supervision and approval by a master electrician will generally be required. The geographical or temporal availability of employees is another such qualifying factor. The more freely tasks can be assigned or rescheduled within the workforce, the more closely quantitative and qualitative requirements will generally align, simplifying operational planning and management.
Calculating current staffing requirements: formula and example
The calculation used to determine staffing requirements is not particularly difficult in principle. The main challenge is usually ensuring that the required data is as accurate as possible.
Step 1: Operational staffing requirement
How many employees are required to complete a specific task? Depending on each employee’s individual working hours, this figure may vary for the same task.
To calculate this figure, the working hours required for a task are divided by the working hours of the individual employees. The result is the number of employees required.
For example, a frontline team stocks shelves and promotional areas at the various branches of a retail company in a city. This requires around 160 hours per week, equivalent to four full-time equivalents (FTEs) working 40 hours per week. Each employee works 20 hours per week, corresponding to an FTE value of 0.5.
160 working hours ÷ 20 = 8 employees
With a workload equivalent to four FTEs, this results in a headcount of eight employees.
Step 2: Absence rate
Absences due to illness, annual leave or time off in lieu reduce availability and increase gross staffing requirements. To calculate this figure, divide the number of days absent by the number of working days and multiply the result by 100. The result is a percentage.
Example: The year has 220 working days and each employee is absent for 19 days per year due to annual leave or illness.
(19 days absent ÷ 220 working days) × 100 = 8.64% absence rate
Step 3: Reserve requirement
How many employees need to be available as a reserve to compensate for absences? Multiplying the operational staffing requirement by the absence factor gives the reserve requirement.
8 employees operational staffing requirement × 8.64% absence factor = 0.69 employees reserve requirement
Step 4: Gross staffing requirement
This is the number of employees, including staffing reserves, required to handle the stated workload effectively.
7.5 employees operational staffing requirement + 0.69 employees reserve requirement = 8.19 employees gross staffing requirement
Important: there is no such thing as 0.19 of an employee, even with part-time positions. The figure therefore needs to be rounded up to the next whole number. Alternatively, the company can try to reduce absences and optimise processes in order to manage with fewer employees.
Step 5: Net staffing requirement
This is the difference between the actual workforce and the calculated staffing requirement. If the company has too few employees, this figure is positive. If it has enough or too many employees, the figure is zero or negative.
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How can future staffing requirements be forecast?
Current staffing requirements form the basis of operational planning, such as shift planning, workforce scheduling and capacity planning. Future staffing requirements are equally important, however. A distinction is made between short-term requirements, which describe current needs, medium-term workforce requirements planning and long-term workforce requirements planning. The latter is tasked with translating corporate strategy into HR strategy.
When determining future gross staffing requirements, one of two methods is generally used: the estimation method or the key performance indicator method. Both approaches are based on determining future staffing requirements on the basis of current requirements.
The estimation method
This approach is based on the experience of internal experts and managers. In the first step, each of them is asked at a specified point in time to estimate staffing requirements for their area of responsibility over a defined period, broken down by specified qualification groups. This process can also involve several stages. For example, external experts may also be consulted and benchmarks from other companies included.
The results are consolidated, checked for plausibility and supplemented with anticipated workforce movements.
Experience shows that this method produces good planning figures, particularly in small and medium-sized companies.
The key performance indicator method
The basic principle of this method is to use the relationship between a particular business metric and the associated staffing level, together with adjustment factors, to determine future gross staffing requirements. For example, the average revenue per sales employee and the sales team’s revenue targets can be used to calculate how many employees the department will require. For production employees, labour productivity is generally a more appropriate metric.
For the key performance indicator method to provide meaningful results, the relationship between the metric and staffing level must be stable, no structural breaks should be expected and the business metric must be chosen appropriately.
Common mistakes in workforce requirements planning – and how to avoid them
Insufficient data and inadequate tools: Workforce requirements planning can only be as accurate as the data on which it is based and the conclusions drawn from that data. This issue can only be addressed by recording the relevant parameters as accurately as possible and using suitable tools for analysis. Particularly when dealing with large volumes of data, specialised AI tools for workforce planning can be useful.
Rounding errors: It may seem trivial, which is precisely why it is easily overlooked. The more calculation steps that follow a rounding operation, the less accurate the result becomes. Figures should therefore be rounded as little as possible and as late as possible.
Lack of agility: Workforce requirements planning is always an estimate and a snapshot. It can only remain valid for as long as the underlying conditions remain unchanged. If these conditions, the wider economic situation or staffing requirements change as a result of artificial intelligence, workforce requirements planning must be adjusted accordingly. However, because this often still involves considerable effort, adjustments are not always made. One solution can be powerful workforce management software capable of accurately recording data such as working hours, productivity and workforce deployment and analysing it automatically.
Workforce requirements planning with Celero One: real-time data instead of Excel
As workforce management software designed to optimise the frontline experience, Celero One combines the tools and capabilities required for comprehensive and immediate analysis of assignments, highly efficient and flexible workforce scheduling, and strategic qualitative workforce planning and development.
Real-time transparency: Workforce requirements planning can only be as reliable as the data on which it is based. Celero One can therefore capture a wide range of operational data and transmit and analyse it virtually in real time. This includes integrated time tracking, for example, which makes it possible to accurately record the actual time spent per resource and assignment and compare it with the target values defined during planning. Through its wide range of accurate data, analytical capabilities and interfaces with other systems, Celero One provides the basis for reliable workforce requirements planning: accurate and comprehensive data.
Aligning quantitative and qualitative staffing requirements: The greater the overlap between quantitative and qualitative staffing requirements within the workforce, the easier, more flexible and more efficient workforce deployment becomes. This is precisely what Celero One is designed to support. Work instructions created in the Process Manager are structured as a consistent sequence of individual action steps. This makes tasks easier to carry out, ensures quality and enables assignments to be reassigned simply and reliably even when individual employees lack prior experience. Celero One also includes AI-supported automated translation, allowing tasks in the Mobile App to be displayed in different languages at the touch of a button. This makes it considerably easier to delegate assignments within multinational teams and ensures that language barriers are no longer an obstacle.
A second element in aligning quantitative and qualitative staffing requirements is employee development. Celero One enables training to be planned and managed, for example through e-training courses delivered via the Mobile App.
Operational agility: EStrictly speaking, this is not a direct component of workforce requirements planning, but rather an operational capability. However, it plays a crucial role in ensuring optimal workforce utilisation and therefore keeping staffing requirements low. For example, the “Auto-Assign” function in the Booking module can automatically delegate tasks based on the qualifications, experience and availability of individual resources.
Celero One therefore combines two key capabilities that can simplify and improve workforce requirements planning: reducing staffing requirements through the efficient deployment of existing resources and providing a reliable data basis for future workforce planning, including AI-supported planning.
From manual spreadsheets to automated AI planning: Celero One provides the required data
Workforce requirements planning always involves trying to look ahead: How will the company develop? How will the market develop? How will the staffing situation develop? Where will requirements arise, and what will they be? A key component of workforce requirements planning is consolidating and analysing data. The more accurate the dataset, the greater the likelihood of an accurate forecast. AI-supported tools are already better than humans at processing and analysing large volumes of data, for example when predicting the risk of employees leaving and staff turnover. This not only reduces the workload involved in HR capacity planning but also creates new possibilities. Different scenarios can be modelled and plans can be created for different headcounts. However, this depends on having the necessary data available. And that is precisely what Celero One already provides today.
Automate workforce requirements planning with Celero One – request a demo. Do you have any questions? We are happy to help:
FAQ
How do I calculate staffing requirements?
Current staffing requirements are calculated on the basis of the operational staffing requirement, absence rate, staffing reserve and gross staffing requirement. The difference between the required staffing level and the existing workforce is known as the net staffing requirement, which indicates the extent to which the workforce needs to be increased or reduced.
What is the difference between gross and net staffing requirements?
The gross staffing requirement indicates how many employees are required in total to handle the workload, including the reserve requirement. The net staffing requirement is the difference between the gross staffing requirement and the number of employees already in the workforce, i.e. the number of additional employees required.
Example:
24 employees are required. The company currently employs 19.
24 – 19 = 5
The net staffing requirement is 5. This means that five additional employees need to be recruited.
This figure can also be negative. In that case, the company already has enough employees for the forecast workload.
Does Celero One include AI features for workforce requirements planning?
Not yet. Celero One is designed as workforce management software for an optimal frontline experience. In this role, it provides a wide range of the data required for reliable, AI-supported workforce requirements planning.