Duration1, Duration2, Duration3 used to calculate project costs from Resource Sheet

Copper Contributor

I am seeking advice as to how I can calculate resource costs from Duration 1, Duration2 Duration3, etc, and ignore Duration which all costs are currently calculated from. 


Duration1, 2 & 3 are efforts from different companies and resources which I want to account for individually but then they roll up to a project total.


At present, I am planning the project and costing in Excel which is not ideal for building resource estimates and costs. 

3 Replies


First you need to understand that in Project duration is simply a time span. The passage of time accomplishes nothing. What you need to focus on is work. Work is the effort one or more resources expends to accomplish a task. Cost is not duration based, although it may appear that way depending on how resources are assigned, cost is actually based on work.


There is a tendency for new users of Project to report progress by entering a value into the % Complete field, when they should be entering progress into the Actual Work or % Work Complete field.


Do not use the extra Duration fields to track work from different companies. Rather, I suggest you make each company a separate resource and assign them to tasks accordingly. The cost associated with each company can then be viewed either on the Resource Sheet or the Resource Usage view.


Hope this helps.


@John-project Thank you for your reply, i appreciate your replying.


I need further explanation if you have the time and inclination. 


I have a task that has a duration of 51 days with a work effort of 5 days for Vendor1 and 12.5 days Vendor2. 


When I assign a cost of $1 per hour project takes the 51 days of Duration multiplies it by 8 to get 408 hours which then shows in the Gantt Cost as $408 


I need it to show as a total cost of $140  in the Resource cost it would be Vendor1 $40 and Vendor2 $100 


That is not happening, have attached a screenshot.


best response confirmed by dpconsult2025 (Copper Contributor)


I assume the work effort, which is normally expressed in hours, is 40 hours (5 days) for Vendor 1 and 100 hours (12.5 days) for Vendor 2.


The screen shot shows custom fields for TM effort, Change Mgmt effort and DXC effort which I also may assume are the Duration1, Duration2, and Duration3 fields. Extra fields (e.g. Duration1, etc.) are static fields, they have no relationship to Project's scheduling or costing calculations. You have assigned resource DXC to the task and if you are getting a task cost of $408 then you apparently have assigned DXC, whose standard rate is $1/hr, at 100%. Project will therefore linearly spread that assignment over the full 51 days of task duration.


Here's what you need to do. Forget the custom Duration fields to entering/tracking vendor effort.

1. Create three resources on the Resource Sheet, Vendor 1, Vendor 2, Vendor 3, each with an hourly rate of $1/hr.

2. Create a Fixed Duration type task of 51 days.

3. Assign Vendor 1 and Vendor 2 at 100%. That will initially give the following result


4. Switch to the Task Usage view. Edit the Work hours for each resource assignment as shown. Note Project will automatically linearly spread each resource's hours over the full 51 day task duration. If you want the spread to be different, manually edit the timescale data (right side of view) as needed.


Does that give you what you need?


Many times when an external supplier (e.g. contract, vendor, etc.) is needed for a plan, that supplier has a fixed price contract to do whatever work is required. Is that better describes your scenario, then that cost is handled differently.