Actual costs are determined through purchase prices, expenses, and production quantities and are compared to standard costs through variance analysis. Variances between actual and standard costs can result in changes to product costing and are used to determine profitability and make management decisions. At month-end, work in process, variances, and cost settlement are calculated to close out the posting period and avoid transactions affecting previous periods. Input and output variances are analyzed to understand differences between planned and actual costs.