The methodology is based on actual data on milk yield, lactation and all costs and revenues obtained from several farms in the Czech Republic and thus gives the possibility of assessing and estimating the profitability of milk production at different open days and facilitating breeder’s decision in dairy herd management. An on-line program called ekomodel is an easy to use tool to improve the profitability of milk production. The methodology uses new methods of calculating the break-event point of price and production, i.e. situation where the costs are equal to the revenues and therefore the zero profit. Czech dairy farmers thus provide information on the possibilities of achieving a positive economic result and increasing their competitiveness.