Choosing the right moment to formally launch a sole proprietorship is one of the first financial and legal decisions a future entrepreneur faces. While intuitively, selecting the first day of the month as the start date seems the simplest solution, from the perspective of optimizing social security contributions, this isn't the best idea.
In practice, it is crucial to precisely distinguish between the technical registration of the application in CEIDG and the formal start date indicated in the application. It is the latter date that fully defines the moment in which obligations to the Social Insurance Institution (ZUS) arise and determines the rules for calculating preferential periods.
The primary argument against starting a business on the first day of the month is the rules for calculating the duration of the so-called Start-up Relief. Pursuant to Article 18, Section 1 of the Act of 6 March 2018 – Entrepreneurs' Law, exemption from the obligation to pay social security contributions is granted for a period of six full calendar months from the date of commencement of business activity.
The method of calculating this period depends directly on the moment when the entrepreneur formally debuts on the market.
When starting a business on the first day of the month, that month is legally treated as the first full calendar month. Consequently, the six-month relief period ends at the end of the sixth month, drastically shortening the period of benefit.
When starting a business on each subsequent day of the month, the first, partial calendar month is not counted towards the statutory limit of six full months. This means that the entrepreneur effectively almost seven months without having to pay social security contributions, paying only health insurance contributions in the first month.
Similar rules and legal and financial consequences apply to the next stage of preference, which is social insurance contributions under the so-called preferential ZUS (paid on a reduced basis for 24 calendar months). The Social Insurance System Act explicitly states that a 24-month period counts as full calendar months.
This comparison shows that postponing the start date of the business by just one day – from
from the first to the second day of the month – it actually extends the total time of legal cost reduction
public-law companies by nearly 30 days over the entire preferential cycle.
Therefore, if we start our business on June 1st, that month will constitute the first full month of the preferential period. However, if the entrepreneur selects June 2nd as the start date, then June becomes an "additional" period, and the actual six-month Start-up Relief period begins on July 1st. As a result, the entrepreneur gains a legal extension of the preferential period.
This article is for informational purposes only and does not constitute legal advice.
The law is current as of June 1, 2026.
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