So I have got an equipment tracking spreadsheet which uses a start date column, and an end date column to calculate projected costs. I want to devise a formula that will go thorugh the sheet and cost loads the schedule by month. So, if a say a bulldozer is rented from 1/5/2012- 6-8/2012, I need the formula for the month of May to sum the costs of this equipment and others that will be rented during the month of may.

I will appreciate any ideas and suggestions.

Thank you.