The planning fallacy: Why we all assume we have more time than we actually do each week (and how to fix it)

How many hours do you work each day? If you’re like most of the working population you probably think you get a solid 8 hours in. That’s 40 hours a week. Around 2000 a year (minus 2 weeks’ vacation). Not too bad.

The problem with this kind of thinking is that just because we’re at work for 8 hours a day, doesn’t mean we’re doing 8 hours of work. (In fact, pretty much every statistic puts that number significantly lower.)

Assuming you have more time than you do is the quickest route to stress, overwork, a lack of productivity, and eventually, burnout.

So, why does the myth of the 40-hour work week still persist. And if we don’t have 8 hours a day to do work, how much time do we actually have?

At best, you have 2.5-3 hours a day to do focused work

Let’s cut to the chase, according to psychologist Ron Friedman, most people “typically have a window of about three hours where we’re really, really focused.”

Our own data backs this number up as well. When we analyzed over 225 million hours of working time, we found that the average knowledge worker (someone who deals with information for a living, like a writer, developer, designer, or manager), is only productive for 12.5 hours a week. That’s roughly 2.5 hours a day.

That’s a far cry from the 40 hours we all assume we have. So why are we overestimating our available time by 3X every single day?

To figure this out, let’s make some gross generalizations about what the average workday looks like, what we want to do, and what actually happens.

We were all hired to do some sort of core work

When you got hired, it was to do some specific task that you’re especially good at. Maybe that’s writing, or designing, or coding. Whatever it is, that’s what we like to call your “core work.”

If you were to plan a perfect week, you’d most likely schedule the majority of your time to do this type of work.

Now, that’s in an ideal world. Instead, here’s what usually happens.

First, add up all the time that you spent in meetings last week and subtract that from your 40-hour week. This number depends on your company size, culture, and job role. But let’s go on the low end and say 15%.

Next, let’s get rid of all the time spent doing the tasks that support your “core work.” This means communication and email.

In general, we’ve found that people tend to spend 25–30% of their computer time at work on communication like email, work chat like Slack, or video calls like Skype, Zoom, or Google Hangouts.

Again, let’s be optimistic and only subtract 2 hours a day for communication.

Planning fallacy - communication overload

Lastly, we need to talk about all that time spent working in a less than optimal way.

From our own research, we found that most people multitask during 40% of their productive time. It’s widely agreed that multitasking can have seriously negative effects on your ability to do good work. So let’s block those out as well.

Planning fallacy - full scheduleAnd there we have it! A realistic week of work.

The problem with the planning fallacy (and why we always think we can do more than we can)

If your math works out like ours, you’ll end up with about 1 hour and 12 minutes a day for focused, productive work.

If you planned your day assuming you would have 8 hours of time for productive work, and you end up with just over one hour, it’s going to be really frustrating. .

Even worse, you’re going to keep adding more and more to your plate, thinking you have all this extra time to do “core work” each day.

It’s upsetting. But it’s also human nature.

For decades, psychologists have called this behavior the Planning Fallacy—our bias towards being overly optimistic when it comes to how much time is needed to complete a future task.

In other words, we’re notoriously bad at looking into the future and figuring out how long a task will take us.

The Planning Fallacy has been blamed for everything from late mid-term papers to billions of dollars of unexpected costs on airports, opera houses, and other development projects. It’s a serious issue, and one that we have to work through if we’re going to do good, focused, meaningful work.

So, how do we get over our optimistic bias?

We need to realign what we think we can do in a day and what we actually can do, which is no small task.

Here are a few proven ways to help yourself become more realistic about what can be done in a day.

Use implementation intentions

One of the biggest issues when it comes to planning our days is not taking the time to really break down what needs to be done. We all have good intentions. But research has shown that intentions only account for 20–30% of our behaviors.

Implementation intentions are concrete plans that accurately show how, when, and where you’re going to do your work. So for example, instead of saying:

“I’m going to write a blog post today.”

An implementation intention would be:

“I’m going to research and write the outline for a blog post on the planning fallacy from 9–11 am, Tuesday morning.”

A good implementation intention also includes an “if-then” plan for when things go wrong.

So, “If I get distracted while writing by a coworker, then I will ask them to come back after 11 am.”

When researchers studied groups who had made implementation intentions like this, they found they began work on the task sooner, experienced fewer interruptions, and were better able to judge how long future similar tasks would take them.

Try the “100 blocks a day” method

Perspective is a powerful tool when you talk about scheduling your time. And just like we shower above when breaking down the average workday, you can do this for your entire day.

According to the writers at Wait But Why, if you sleep 8 hours a night, that leaves you with about 1,000 waking minutes a day to schedule. Or, 100 10-minute blocks.

Lay those blocks out on a grid and ask yourself, how many are:

  • Put towards making your future better, and how many of them are just there to be enjoyed?
  • Spent with other people, and how many are for time by yourself?
  • Used to create something, and how many are used to consume something?

“You’d have to think about everything you might spend your time doing in the context of its worth in blocks. Cooking dinner requires three blocks, while ordering in requires zero—is cooking dinner worth three blocks to you? Is 10 minutes of meditation a day important enough to dedicate a block to it?”

This isn’t necessarily a practice any (sane) person would go through on a daily basis, but the idea behind it is sound. Know you have a finite amount of time each day and see how many blocks you have.

Take an outside view

Have you ever noticed how much easier it is to give advice than to take it yourself? The same thing happens when we’re trying to schedule our time.

Studies have shown that the planning fallacy vanishes when you’re forecasting how long a task will take someone else. This is called taking an “outside view”. So, we’re overly optimistic with our own abilities and more realistic with others.

To get over this, you can use what’s called “Reference class forecasting”, which is basically a fancy word for switching your thought process from “how long has this taken me in the past?” to “how long does this type of project take people like me?”


One of the most frustrating things about the modern workplace is not feeling like you’re making meaningful progress. And while you might get paid for 40 hours of work each week, you can’t realistically schedule 40 hours of work.

We all have biases that get in the way of scheduling our days properly. Only by understanding and acknowledging them are we able to set ourselves up for success.

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Jory MacKay

Jory MacKay is a writer, content marketer, and editor of the RescueTime blog.