Calculating salary for the part of a month worked is one of the most important elements of HR and payroll in any company. Labour law sets out precise rules on how to determine what an employee is owed when they do not work for the whole calendar month. Understanding these rules is essential for the HR department to work properly and avoid potential legal problems.
The Labour Code (Kodeks pracy) establishes a basic rule of paying salaries monthly, but in practice employees often do not work for a full month for various reasons. This may be due to illness, unpaid leave, starting or ending employment during the month, or other circumstances provided for by law. Each of these situations requires the relevant rules and calculation methods. Employees also ask whether they may earn money elsewhere in that time — our article on working for another employer during unpaid leave answers this.
The employer must use different methods to calculate salary for the part of a month worked, depending on the reason for the employee's absence. An incorrect calculation may lead to claims by the employee or to problems during an inspection by PIP (National Labour Inspectorate)
Basic rules for monthly salary
The Labour Code establishes the general rule of a monthly pay cycle, which is the foundation of the whole system of employee settlements. Under Article 85 § 1 of the Labour Code, salary is paid at least once a month, on a fixed date set in advance. This rule gives employees predictability and regularity in receiving payment for their work.
Salary paid once a month is paid in arrears, which means that the employee receives payment after the work for the given period has been done. Payment is made promptly after the full amount has been determined, but no later than within the first 10 days of the following calendar month. This rule gives the employer time to carry out all the necessary calculations and settlements. We prepare payroll, including pay for part of a month, as part of our payroll outsourcing.
If the fixed payday falls on a day off work, salary is paid on the preceding day. This rule ensures that employees have timely access to their pay regardless of the calendar of days off
The rules also allow some pay components to be paid less often than monthly. Under Article 85 § 4 of the Labour Code, pay components due to the employee for periods longer than one month are paid in arrears on the dates set out in labour law. This applies, for example, to quarterly bonuses, annual awards and other periodic benefits.
The employer must pay salary at the place, on the date and at the time set out in the work regulations or other labour law provisions. Salary is paid in cash; partial payment in a form other than cash is allowed only if statutory labour law provisions or a collective labour agreement provide for it.
Modern technology allows flexible ways of paying salary. Salary is paid into the payment account indicated by the employee, unless the employee has submitted, on paper or electronically, a request to be paid in person. This rule in Article 86 § 3 of the Labour Code takes into account employees' preferences and employers' technical capabilities.
Legal basis for salary for part of a month worked
Under the principle in Article 80 of the Labour Code, salary is due for work performed, and for time when no work is performed the employee keeps the right to salary only where labour law provides for it. Where the employee did not work for part of the month, the employer must reduce the salary accordingly and pay for the time worked.
Salary for the part of a month worked must be calculated separately, based on the relevant provisions, which set different rules. The basic rules include Article 81 of the Labour Code on pay for downtime, Article 92 and the provisions of the Act of 25 June 1999 on cash benefits from social insurance in the event of sickness and maternity.
When determining salary for work performed during part of a month, apply the Regulation of the Minister of Labour and Social Policy of 29 May 1996 on the method of determining salary for periods when no work is performed
The rules on holiday pay in Article 172 of the Labour Code and the Regulation of the Minister of Labour and Social Policy of 8 January 1997 on the detailed rules for granting annual leave, determining and paying holiday pay and the cash equivalent for leave are also important. They also apply when settling final pay when employment ends mid-month.
In addition, take into account the Regulation of the Minister of Labour and Social Policy of 15 May 1996 on the method of justifying absence from work and granting employees time off work. Together, these rules form a comprehensive legal system for calculating salaries correctly in different situations of employee absence.
The key legal act is the Regulation of the Minister of Labour and Social Policy of 29 May 1996 on the method of determining salary for periods when no work is performed and the salary forming the basis for calculating compensation, severance pay, equalisation allowances and other payments provided for in the Labour Code. This regulation contains detailed calculation methods for different cases.
Calculating salary in the case of illness
Special rules apply when calculating salary for the part of a month worked if, for the rest of the month, the employee received sick pay under Article 92 of the Labour Code or a benefit under the rules on cash benefits from social insurance in the event of sickness and maternity or under the rules on social insurance against accidents at work and occupational diseases.
Under § 11 of the regulation (consolidated text: Journal of Laws (Dz.U.) 2017 item 927), to calculate salary set as a fixed monthly rate for the part of a month worked in the case of illness, you divide the monthly rate by 30 days. The result is multiplied by the number of days stated in the medical certificate of the employee's temporary incapacity for work due to illness.
The method of calculating salary in the case of illness is based on a fixed divisor of 30 days, regardless of the actual number of days in the given month. This rule ensures consistent calculations and simplifies HR procedures
The method can be illustrated with the following example: if an employee did not work because of illness from 1 to 10 July and worked from 11 to 31 July, with a monthly rate of PLN 5,400, the calculation is as follows:
- Divide the monthly rate by 30 days: PLN 5,400 : 30 = PLN 180
- Multiply by the number of days of illness: PLN 180 x 10 days = PLN 1,800
- Deduct from the full salary: PLN 5,400 - PLN 1,800 = PLN 3,600
The amount of PLN 3,600 calculated in this way is the employee's salary for the part of the month worked. As a rule, this method is used in all cases where the employee's absence results from incapacity for work due to illness confirmed by a medical certificate.
Calculating salary for other absences
Where the employee was absent from work for reasons other than incapacity for work due to illness and does not keep the right to salary for that absence, a different calculation method applies. Under § 12(1) of the regulation, the monthly rate is divided by the number of hours to be worked in the given month.
The result is multiplied by the number of hours of the employee's absence from work for those reasons, and the amount calculated in this way is deducted from the salary due for the whole month. This method takes into account the actual working time to be performed in the specific month, which makes the calculation more precise.
The method of calculating salary for absences for reasons other than illness takes into account the number of hours to be worked in the given month. This allows the employee's pay to be determined more precisely in proportion to the time of absence
The method can be shown with the example of an employee who, according to their working time schedule, works Monday to Friday for 8 hours a day. If from 6 to 9 October 2026 (Tuesday to Friday) the employee was on unpaid leave, the absence covered 4 days, or 32 hours. In October 2026 there are 176 hours to be worked (22 days from Monday to Friday × 8 hours, Article 130 of the Labour Code), and the monthly salary is PLN 6,200, so the calculation is as follows:
The first step is to set the hourly rate by dividing the monthly salary by the number of hours to be worked: PLN 6,200 : 176 hours = PLN 35.23 per hour. Next, calculate the value of the absence: PLN 35.23 x 32 hours = PLN 1,127.36. Finally, the salary for the part of the month worked is: PLN 6,200 - PLN 1,127.36 = PLN 5,072.64.
Special cases of calculating salary
The method of calculating salary for the part of a month worked set out in § 12(1) of the regulation also applies when calculating the salary of an employee paid a fixed monthly rate whose employment does not cover the full month. This applies when employment starts or ends during the calendar month.
A practical example is a situation where the employee and the employer agreed to terminate the employment contract on 26 August 2026. This means that from 27 to 31 August the employee is no longer employed, and according to the schedule they were to work on 3 days in that period: from 27 to 29 August. The employee was employed under an equivalent working time system and according to their schedule was to work 12 hours on 27 August, 6 hours on 28 August and 10 hours on 29 August, a total of 28 hours.
If the employment contract ends during the month, salary is calculated in proportion to the time the employee was to work according to their working time schedule. Both standard and equivalent working time systems are taken into account
In August 2026 there are 160 hours to be worked (21 days from Monday to Friday × 8 hours minus 8 hours for the public holiday on 15 August, which falls on a Saturday, Article 130 § 1–2 of the Labour Code), and the monthly rate is PLN 4,900, so the salary for the days worked from 1 to 26 August is calculated as follows:
| Calculation step | Value | Explanation |
|---|---|---|
| Hourly rate | PLN 30.63 | PLN 4,900 : 160 hours |
| Value of absence | PLN 857.64 | PLN 30.63 x 28 hours |
| Final salary | PLN 4,042.36 | PLN 4,900 - PLN 857.64 |
The methods presented for calculating salary for the part of a month worked are based on the general assumption that the amount of such salary should be proportional to the time worked. This principle of proportionality ensures fair treatment of employees and correct settlements in different situations of absence from work.
Step-by-step calculation procedure
Correctly calculating salary for the part of a month worked requires a systematic approach and the right procedures depending on the reason for the employee's absence. The process can be divided into several key stages that ensure accuracy and compliance with labour law.
- Determine the reason for the employee's absence from work
- Choose the right calculation method in line with the rules
- Collect the necessary data on salary and working time
- Carry out the calculation using the correct formula
- Check the calculation and document the process
- Enter the results into the payroll system and prepare the payment
The first stage is to determine precisely the reason for the employee's absence, because this decides which calculation method applies. If the absence results from illness confirmed by a medical certificate, you divide by 30 days. For other unexcused or unpaid absences, you divide by the number of hours to be worked in the given month.
Documenting the reason for the employee's absence is key to choosing the right calculation method. A medical certificate, a request for unpaid leave or other documents determine how salary for the part of a month worked is calculated
The second stage requires precise application of the relevant legal provisions. For sickness absences, § 11 of the regulation applies, and for other cases § 12. Each method has its own calculation rules, which must be followed strictly to avoid errors and potential employee claims.
The third stage involves collecting all the necessary figures, such as the monthly rate, the number of days or hours of absence, the total number of working hours in the month and the periods of absence. This information must be carefully checked and supported by the relevant documents.
Practical aspects of applying the rules
Applying the rules on salary for the part of a month worked in practice requires attention to many details and nuances that may affect the final result. HR departments must be prepared for various situations and be able to interpret them correctly under the applicable rules.
One key aspect is correctly determining the number of working hours to be worked in the given month. In standard working time this number may vary depending on the number of working days in the month and the applicable working time schedule. In equivalent systems the calculation may be more complicated because of the varying working hours on individual days.
Equivalent working time systems require special attention when calculating salary for the part of a month worked. You need to take into account the actual schedule of hours planned for the days of the employee's absence, not the average number of hours per day
Another important element is properly documenting all calculations and decisions made when determining salary. This documentation may be needed during an inspection by PIP, in employment disputes or in internal audits. Each calculation step should be clearly justified and possible to reproduce.
Pay particular attention to cases where different types of absence occur in the same month. For example, when an employee was ill for part of the month and on unpaid leave for another part. In such situations it may be necessary to apply different calculation methods to the individual periods of absence.
An employee working under an equivalent working time system was ill for 5 days in the first half of the month and then took 3 days of unpaid leave in the second half of the month. For the period of illness the method of dividing by 30 days was used, and for the unpaid leave the method of dividing by the number of hours to be worked in the month, taking into account the specific schedule of hours on the days of absence.
Most common mistakes and how to avoid them
In practice, mistakes often occur when applying the rules on salary for the part of a month worked, which may lead to incorrect settlements and potential legal problems. Knowing the most common mistakes and how to avoid them is essential for HR departments to work properly.
One of the most common mistakes is using the wrong calculation method for the reason for absence. Some HR departments use a single method for all absences, which leads to incorrect results. It is always essential to check whether the absence results from illness confirmed by a medical certificate or from other reasons.
Another common mistake is incorrectly determining the number of working hours to be worked in the given month. This can be particularly problematic in equivalent systems, where the number of hours may differ significantly between months. Always check the working time schedule in force for the specific month.
Mistakes in calculating salary for the part of a month worked may lead to employee claims for additional payment or to the need to recover overpaid amounts. Regular training for HR staff and checking calculation procedures are essential to avoid such situations
Misinterpreting the documents confirming the employee's absence can also be a problem. Medical certificates, requests for unpaid leave and other documents must be carefully analysed for dates and periods of absence. Every day of absence must be correctly classified and taken into account in the calculation.
Another important aspect is correctly including all components of the monthly salary. Some HR departments may leave out certain pay components or include components that should not be taken into account when calculating salary for the part of a month worked. Always check which components are set as a fixed monthly rate.
To avoid mistakes, it is recommended to:
- Provide regular training for HR staff on the applicable rules
- Develop clear calculation procedures for different situations
- Introduce a system where calculations are checked by a second person
- Keep detailed documentation of all calculations
- Regularly update knowledge of changes in labour law
