How to Estimate with the Estimating Formula

If you want to estimate it helps having a formula.

Accurate estimating is a valuable skill. It's the answer to the question "How long will it take?"  If your boss, user or customer asks this question and you answer it incorrectly it could be a problem of

• Working overtime
• Not meeting expectations 
• Not being trusted
• Receiving a lower hourly rate for your work

If your boss asks for an estimate and you underestimate the work you may be working lots of overtime to meet your commitment. Had you had an accurate estimate you could tell him what that is and hopefully not work the overtime.

If you estimate time to build a website at 10 hours, $100/hour then you'll quote a price of $1,000. But what if your estimate is wrong and it takes 30 hours. It can be hard to charge the $3,000 you worked. Don't plan on getting repeat business. An accurate estimate would allow you to do better to come in on time with the site.

The formula for accurate estimating can be answered with the question of when will you finish this 300 page book? I use the book example, because once you understand it, estimate other things will be a matter of collecting the proper information and applying the formula.

Now if you read a page a minute it will take you 300 minutes or 5 hours (300/60) to complete the book. This is the actual time to read the book but not the elapsed time. If you read an hour a day it will take you 5 days to complete it. If you read 1/2 a day then 10 days to complete it. 

This brings us to the formula 

Estimated Completion Date = 

                                                                  pages to read 

        Today's Date  +       ---------------------------------------------------

                                       Pages per min  x  Time reading each day in minutes

So this is the basics of the Estimating Formula.  This formula will soon be implemented in Time-Creator.com, but it does help you with the variables of Pages/minute and Time reading each day.

You can download as spreadsheet to see this calculation in action.

If want job security, more customers, better employment reviews it does start with simple accurate estimating.