Units and Peak Units in MS PROJECT 2010! What are they?


I got this comment from one of my Blog readers: “I’ve seen there is a bug on calculation of USE!
there are 2 conditions of fault:

a) fixed work,,, you change duration… nothing happens to resource % use
b) fixed Duration … you change work … nothing happens to resource % use BUT is not deeply true!!!

if you goes to “resource diagram” the % is recalculated,
I think something is missing in the code.
It’s a pity because for me the automatic calculation of use% was very useful!!!!”

Is this a Bug in MS PROJECT 2010 or MS PROJECT 2013? No, it is not. But it is confusing thing. Let me explain it to you!

First I will add one simple Task in My Project:


and I will add two Resources , as well:


Now I will assign both Resources to the Task:


and I will set up Detailed View:


and then:


and I will get:


Now suppose that my Task is Fixed Duration:


As you remember from my Previous Post, the Relation between Units, Duration and Task is: DURATION * UNITS = WORK

Now suppose that I change hours for John from 40 to 60, and for Mary from 40 to 20:


and I will get:


So let us look at the Magic Formula: DURATION * UNITS = WORK.

  • For John: 5 days (5 days * 8 hours per day) is 40 hours * 100% = 40 hours
  • For Mary 5 days (5 days * 8 hours per day) is 40 hours * 100% = 40 hours

Where is the Catch? It seems like a bug. It should be:

  • For John: 5 days (5 days * 8 hours per day) is 40 hours * Units% = 60 hours, so Units% = 60/40 = 1,5 e.g.. 150%
  • For Mary 5 days (5 days * 8 hours per day) is 40 hours * Units% = 20 hours, so Units% = 20/40 = 0,5 e.g.. 50%

Now I will use a Task Usage View:


and I will get:


I will add new Column: Peak!


and I will get:


So the Magic formula is: DURATION * (Peak) UNITS = WORK.

The same thing is if you use Fixed Work Task Type!

If you want some further and Detailed description please read this article:




About Nenad Trajkovski

Location: Zagreb, Croatia Occupation: Project Manager Interests: Project Management and MS PROJECT He was born in Zagreb, Croatia at 1963. After completing his college he started working on projects in different business areas (banking, manufacturing, automotive industry, distribution, oil companies, etc.) developing and implementing ERP systems into different companies. He has got a lot of experience working with people in different business processes and also possesses great knowledge in information technologies and financial services. Today he works as a business consultant, adn Project Manager in PERPETUUM MOBILE d.o.o. Zagreb. He is a regular lecturer for Project Management in MS Innovation Center in Varaždin, Logosoft Sarajevo in Bosnia and Herzegovina and SEAVUS GROUP in Skopje Macedonia. He was named the best lecturer of WINDAYS 2008 while his lecture was also voted as the best. In addition, he was in TOP 10 lecturers at the MS SINERGY 2009 and MS VISIA 2009, 2010. Shares first place as the best lecturer of KulenDays 2009 and 2010 and PMI Conference 2009 in Zagreb. He is also a regular lecturer in the MS Community. He is a Certified Accountant and a PMP (Project Manager Professional) and a PMI-RMP (Risk Manager Professional), MCP, MCT, and Microsoft Certified Technical Specialist - Microsoft Project 2010. From 01.01.2012 awarded with MVP (Microsoft Most Valuable Proffesional - Microsoft Project)!
This entry was posted in MICROSOFT PROJECT, Microsoft PRoject 2010, Microsoft Project 2013, MS PROJECT 2010, PMI and tagged , , . Bookmark the permalink.

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