Software Project Estimate Excel Template and Example

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Free Software Project Estimate Template in Excel / Google Sheets  The template below has been successfully used in dozen of software development project. It calculates total project effort based on development estimates.  You can finetune the template to your project by adjusting corresponding percentages. Please follow the steps below to obtain full and realistic project estimate. Free Excel Software Project Estimate Template Free Google Sheets Software Project Estimate Template How to use this template Please follow the steps below to obtain full project estimate. Fill-in the cover.  It is important to list all the assumptions that make your estimate relevant. They may include the versions of frameworks, agreements with your client or contractors, disputable points in project scope definition, requirements etc. Place them onto Assumptions sheet. Create a WBS for your project. Noun-based WBS is preferable. List the work items in ESTIMATE sheet. Carefully read the contrac...
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Units of Measure for Project Effort Estimate

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Effort vs Duration

I prefer to estimate project effort (in MAN-HOURS) rather duration (in days or weeks) for the following reasons:

  • At estimation time your team, its capacity, working calendars and project allocations are often unknown and thus you cannot estimate work duration adequately.
  • It is easy to roughly estimate the project duration by simply dividing the estimated effort by the available resources. 

Why MAN-HOURS?

  • Different people, teams and countries work by different calendars. Workweek can be 20 work hours for one person and 50 for another. And an hour is pretty much always an hour.
  • Outsourcing rate are often given for man-hour. It is easy to estimate your project budget in dollars simply multiplying by market hourly rate.
  • Billing is typically done by man-hours.
  • Time tracking is typically done in hours, It is much easier to compare hours vs hours if you need to do so.
  • Estimate in hours are by definition more precise and make developers be more responsible and look deeper.

Powers of two

I find it convenient to give estimates in man-hours in powers of two: 0.5, 1, 2, 4, 8, 16, 32.
They add up well to workdays, weeks and also correspond well to task sizes:
  • 0.5 mh - minimal possible task
  • 2 mh - time a person can work without distraction and rest
  • 4 mh - half a workday
  • 8 mh - a workday
  • 32 mh - almost workweek

Effective hours vs Work hours

It is not a secret that developers can hardly work effectively more than 5-6 hours of standard 8 hours workday. The rest goes for rest, Internet surfing, coffee, talks and other personal matters. Nevertheless, I recommend to use work hours in estimates because:

  • It can be really hard to explain to your customer why they pay for 8 hours and your people only work 6.
  • Use of effective hours will required additional coefficients and adjustments to obtain planned duration.
  • Time tracking is done in working hours and it makes plan-fact analysis easier.
That means if your developer has estimated 24 man-hours to complete a task, it will take three full workdays, although he/she will actually work around 15 hours on the task.

On the other hand, a six hour task will take a full workday to complete and if you have many small tasks you may want to adjust your estimates to account for this fact.



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