Hi, You need a formula that calculates the number of workdays between 2 dates for all projects for each month. Off the top of my head I already figured a way to calculate the formula for each month by referencing the end date in your "simulation" worksheet inside your already created formula that calculates "Dynamics". It should look something like that =SUM(NETWORKDAYS('Sales Contractes (market)'!G8,Simulation!C17,workdays!$F$6:$F$15)). Of course this sometimes could give you negative numbers, but you can add an if condition to place a zero if you get a negative number. As for the calculating for each category junior, medior, and senior, I'd like to discuss the possibility of adding some hidden helper columns or even hidden worksheets that will aid us with our formula or even we can discuss creating a custom excel formula using VBA. If you have the time we can chat and discuss how to move forward.