4 Ways to Estimate How Long a Task Will Take

Man looking at his watch by Jeffrey PaaIt can turn the most powerful person into a bunny rabbit in the headlights…


It is the harbinger of doom…


It is the question…


How soon can you get this done?


Your answer to that question affects your credibility. If you underestimate, you are a slacker. If you overestimate, you are a liar. However, accurate estimates are just plain hard. How can you know what fires will be burning tomorrow?  How do you know when someone will poke their head in your door and then all your priorities are thrown to the wind?


When work is unpredictable, all you can do is the best that you can to accurately estimate a turnaround time. What does “the best” look like?  Four suggestions follow.


Four Ways to Estimate Turnaround Times


1. Look at your calendar and task list


Sure, a request from a coworker may take you around 30 minutes to complete, but when will you have that dedicated half hour to devote to the request?


The best way to give an honest estimate of how long a task will take is by seeing when you can realistically fit it in to your schedule. That’s why “Let me check my calendar and task list and get back with you by close of business today” is a perfectly wonderful answer to “When can you get this done?”


However, to be able to check your calendar and task list, you…well…must have an updated task list and a calendar. Easier said than done, but nothing is more essential to your productivity.


If you don’t have these two tools of productivity, you will likely either: 1. drop everything to do the request immediately for fear of forgetting it, thus ignoring other priorities, or 2. fool yourself with a statement such as “Oh, I surely can remember to do that later,” and then frustrate the requester when you inevitably forget.


Here are the essentials of calendar and task management:
  • Use your calendar for your time-of-day-dependent events and appointments (e.g., meeting at 9 am, dentist appointment at 3 pm). That is how you manage your non-discretionary time.
  • Block off some time on your calendar to complete tasks and honor those time blocks. This helps you plan and manage your discretionary time.
  • Maintain a separate list of tasks (a.k.a., to-dos, action items, etc.). You are fired from the job of remembering your tasks.
  • Assign a progress date to every task on your task list. A progress date is the date on which you wish to make progress on a task. To see what you need to do each day, sort your list by progress date.


So, the coworker comes up to you with a request for a 30-minute task. You open your calendar and your task list (I really like Outlook Tasks because it can show them both in the same screen), and say…


“The earliest I can add this to my task list is next Tuesday.”


Then, you add the request to your task list with a progress date of next Tuesday.


2. Track your typical turnaround times


This does not have to involve a stopwatch or a scientific research study. For two to three weeks, track the requests you receive and how long it took you to complete them. This can be done in a spreadsheet or paper notebook. The best predictor of future behavior is past behavior. Know your numbers.


If you are plagued by interruptions that make it difficult, if not impossible, to track your turnaround times, you need to attend my free webinar: The Anatomy of an Interruption…and how to resume work when they happen. At the end of the self-paced webinar, you can receive some free templates to help track your interruptions and reduce the time suck they often cause.

The Pomodoro Technique® is a proven method of getting work done. It involves working in 25-minute sprints (called “pomodoros”) with short breaks in between. It is also a good way to get to know your typical turnaround times. For example, if you learn that it typically takes one pomodoro to produce Report X, or two pomodoros to finish Task Y, then you can better estimate your turnaround times.


Besides, the bewildered expression on a coworker’s face when you say, “Well, I think that request will take me two and a half pomodoros to complete” will add variety and fun to your workdays.


3. Use the Montgomery Scott approach


I am going to totally age myself now…


In Star Trek III: The Search for Spock, Scotty reveals to Captain Kirk that he is known as the Miracle Worker because he routinely multiplies his time estimates by a factor of four.


It may sound ridiculous, but some programmers and engineers can attest to the validity of the approach.


Although this is the easiest of the four methods to make sure you don’t miss deadlines, it can also be the most dangerous. Exaggeration may work for a while, but eventually, your boss and coworkers will catch on to the game.


One way to turn exaggeration into “smart planning” is to confess to the requester that you are adding a cushion to your estimate. A simple statement of “I think I can get to this on Friday but give me until Tuesday as a cushion for any emergencies.”


Cushions are great. In fact, if you are often late to meetings, adding a 15-minute cushion to all your travel/transition times can help.


4. Calculate a Weighted Average


For the mathematical people in the world, yes, there is an equation to help you estimate turnaround times. It comes from the world of project management.


To estimate the time needed to complete a project consider the following:

  • The most optimistic turnaround time
  • The most likely turnaround time
  • The most pessimistic turnaround time


Then, you calculate a weighted average of these three numbers:

O + (4L) + P


Here’s an example of a productivity consulting project I led for a client last year:

  • Optimistic estimate = 3 weeks
  • Likely estimate = 6 weeks
  • Pessimistic estimate = 12 weeks

3 + (4 x 6) + 12 / 6 = 6.5 weeks


While my instincts are to tell my clients the most likely estimate, the weighted average technique reminds me to allow a little extra time.


The weighted average technique is also a good one for the chronically tardy. If you plan all your travel times based “that one time” when you got there in 10 minutes (the optimistic estimate), you have a one in six chance of being on time.


All four techniques above necessitate diligence and the ability to manage your tasks well. If you are struggling with time or task management, contact me for an initial assessment (at my expense) to see if productivity coaching can help.


Final thought:  If you know that you are going to miss a promised deadline, come clean about it as soon as you know you’ll be late. Notify the requester that, despite your best efforts, you will need more time. Most people understand because they experience it themselves. Learn from the experience and estimate better next time.


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Dr. Melissa GratiasMelissa Gratias (pronounced “Gracious”) used to think that productivity was a result of working long hours. And, she worked a lot of hours. Then, she learned that productivity is a skill set, not a personality trait. Now, Melissa is a productivity expert who coaches and trains other businesspeople to be more focused, balanced, and effective. She is a prolific writer and speaker who travels the world helping people change how they work and improve how they live. Contact her at getproductive@melissagratias.com or 912-417-2505. Sign up to receive her productivity tips via email.


  1. Seana Turner

    Well that was pretty cool! My friend Hazel is going to love this one:) I love a little math and how it can help us think through things. Estimating time is always difficult. I feel like, during this time of COVID, I would also need to double the time for all projects LOL. Time seems to have slowed down!

    • Hazel Thornton

      LOL, I do love it, Seana! (And Melissa!) And I agree that time seems different these days. Sometimes it seems that time is slower — wasn’t March the longest month e.v.e.r.? — but sometimes I think it’s just ME that’s slower — wait, what happened to May?

      I especially agree with the last part. Don’t ever leave them wondering! If you’re running late and haven’t admitted it yet, do not let the deadline pass without a status update!

      • Melissa Gratias, Ph.D.

        I think March was four and a half years ago. No one can convince me otherwise. Be well, Hazel.

    • Melissa Gratias, Ph.D.

      I agree. Time is passing very much like a Doctor Who episode for me . Today, a friend sent me a link to an interview with Dr. Tim Pychyl who asserts that we need to find better ways to cope with the current situation, not give ourselves license to delay our tasks and projects. Argh. Maybe I’ll find better coping mechanisms tomorrow…

  2. Linda Samuels

    Often I think we aren’ t time realists. We use “aspirational” thinking, rather than considering all of the competing time factors. I love the different methods you shared for becoming a better time estimator. I tend to use the #1 approach, which for me, is visual. My calendar has color time blocks for appointments, so some of the white space I use as my “opportunity time” to handle tasks and projects. I like #3 too. Go Star Trek!

  3. Rebecca Watkins

    So true! I needed this as it is hard for me to estimate my art turnaround for commissions. I have a system (to overestimate) in place, but I really like some of the other methods and think the mathematical approach may be better than my Scotty approach!

    • Melissa Gratias, Ph.D.

      Nothing wrong with a little Scotty from time to time, Rebecca! I also think that tracking your commissions, the size of the canvas/complexity of the work, and the hours spent on each would be a good tool for you. A nice side benefit would be that it would also make sure you are pricing (and pacing) your work appropriately.

  4. Julie Bestry

    Fractions? I was told there would be no math homework on this blog! I’ll do alternate math — likely estimate plus one-half of optimistic. My way, it’s 7.5 weeks; longer than yours, but probably less panic-inducing for the listener than Mr. Scott’s approach. That said, that only worked in the before-times; in a pandemic/quarantine situation, time has no meaning. But your advice is excellent, as always.

  5. Dennis Fox

    One silly estimating tool for projects is the “Tool Time” method from the show with the same name.
    1. Make your best estimate.
    2. Double your estimate.
    3. Change the units to the next unit of time.
    Example: Estimated 2-hour job become 4-days. Estimated 10-minute task becomes 20-hours.
    Especially in projects that require reliance on others such as vendors or customers, this formula is uncomfortable accurate.

    • Melissa Gratias, Ph.D.

      Love it! It seemed to work for Tim “The Tool Man” Taylor, right?


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