The study attempts to forecast the total costs of a company in Poland. The first stage of the research was analyzing and evaluating the time series of total costs. It detected: trends, seasonality and a random factor. This became a premise for the application of two methods for forecasting: Holt-Winters’ multiplicative and additive. The research shows that the Holt-Winters’ multiplicative model proved to be better in forecasting total costs in the research subject. The forecasted total costs from July to December 2022 will reach PLN 45 395 685, while from January to December 2023, their value will amount to PLN 85 948 927.