Accounting processes play a key role in the correct calculation of Value Added Tax. In the first part, it will be written in general, basically about the value added tax, about its subject of taxation, the taxpayer, the tax base, forms of VAT and the actual calculation of VAT. Value added tax is one of the most important sources of state revenue. It is impossible to calculate VAT without first recording it in the bookkeeping. That is why the second part of the work is based on accounting processes. What exactly are accounting processes and what documents do they contain, what are the stages of the accounting process and bookkeeping records and the narrower part, which are incoming and outgoing accounts. The most important part of accounting, bookkeeping, shows the processing process through three phases: input, processing and output. VAT rules are often complex and subject to change, and a good accounting system allows you to monitor these changes and ensure that the company regularly calculates and pays VAT in accordance with current regulations. Incorrect VAT calculation can create an unwanted risk for the company. Proper accounting records and accurate VAT calculation reduce this risk and ensure that the company does not pay unnecessary taxes. The crucial roles of accounting are in the proper recording of business transactions, differentiation of output and input VAT, monitoring of the VAT rate and preparation and submission of VAT returns to tax authorities. It is discussed in the middle and final part. The work provides an insight into the key elements of accounting processes that are of particular importance for compliance with tax regulations.