The goal of this paper was to describe and explain concepts of light, lighting and to closely show the standards used for lighting in the Republic of Croatia as well to show an example of a lighting estimate. The paper presents and compares the results obtained by measuring lighting at the Technical Faculty in Pula with the values set by the norm. After the measurements, the recorded results obtained for "Office 4 - secretariat" did not meet the HRN 12464-1:2021 norm, and based on them, a proposal for improvement was made in order not to continue working in conditions where the lighting does not meet the norm and may cause unnecessary stress, fatigue and affect mental and physical health. Also, the paper presents a manual and computerized lighting calculation example. The computer calculation example shows how easy it is to use this type of lighting calculation program, and the results of the calculation are done and shown in a quick and simple way.