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Why You Always Underestimate Time (And How to Fix It)

Updated: Oct 16


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Neurodivergent adults often struggle to estimate how long tasks take to complete. This leads to missed deadlines at work, arriving late to appointments, or overplanning their days.


In this post, you'll learn a simple strategy to improve your ability to estimate how long something will take.


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Hi Friend,


Ever notice how difficult it is to estimate how long something will actually take?


I’m not talking about brushing your teeth or driving to work. I mean new projects at work, getting ready to leave the house, or chores at home.


Writing this newsletter is a perfect example. 


Some weeks, the ideas flow. Other weeks, I stare at a blank Google Doc for an hour, write three sentences, delete four, and somehow end up reading the surf forecast for Western Australia. 


Neurodivergent brains, especially those of us with ADHD or who are autistic, are notoriously bad at estimating how long something will take. It's due to executive function skill weaknesses in planning, emotional regulation, and sustained attention. 


But honestly, it’s not just us. Humans have been terrible at this forever.


Just ask the team that built the Sydney Opera House. They thought it would take 6 years and cost $7 million. It actually took 10 years and cost $102 million!


Can you imagine being that far off at work?


So yeah, we’re in good company. 


While our mistakes might not cost millions, we still struggle with the same problem on a smaller scale.


We constantly apologize for being late.

Have numerous one-on-one meetings about our poor work performance.

Feel frustrated and guilty for "not being able to manage our time."

And overplan our days, making it feel like we are always behind.


The truth is, we are just estimating wrong.



So, how do some people manage to stay on track and finish their to-do lists without melting down at 4 PM? 


They’ve mastered one sneaky skill: padding time.


Today, we are improving our executive function skills by learning to estimate how long something will actually take using the same method.  


Let’s dive in. 


Why You Underestimate Time 

It’s nearly impossible to estimate how long something will take for two reasons: 


First, we fall victim to the planning fallacy–our tendency to underestimate time, cost, and effort, even when past experiences prove otherwise.


Then, we forget to consider unpredictable obstacles like:


Getting poor sleep. 

Our boss asking for “one quick thing.” 

The dog tearing up an important bill sitting on the coffee table…


Neurodivergent brains especially struggle here. Adults with ADHD often have a hard time perceiving time (what’s called time blindness). For autistic adults, unexpected transitions or interruptions can derail focus and momentum.


We’re also overly optimistic about our future selves. And even when we try to account for delays, we still underestimate. That’s Hofstadter’s Law: “It always takes longer than you expect, even when you take into account Hofstadter’s Law.


Ouch. 


So if it’s impossible to know how long something will take precisely, what should we do? 


We pad our time. 


How to Estimate How Long a Task Will Take

The goal of padding time is to give it a t-shirt size estimate (S, M, L) and check in with anyone who is waiting on us sooner, rather than later, with an update. 


I teach my adult executive function coaching clients how to do this in four steps:


1) Choose an MIT

Take a look at your to-do list and select the most important task (MIT) for the week. Or, choose any task you want to accomplish. 


It might be checking email, cooking dinner, getting ready, or a weekly report at work.


Example: going to the grocery store.


2) Estimate, then pad 

Estimate how long it will take. Then multiply it by 1.5. 


I think it will take 40 minutes, so I’ll give myself 60. 


3) Track the truth 

Time how long the task actually takes. Over time, you’ll start seeing patterns, and your estimates will get sharper.


Last week, it took 52 minutes, door to door. 


4) Reflect and adjust

At the end of the day, ask: How accurate was my estimate?


This kind of reflection builds metacognition, an executive function skill that helps you learn how your brain actually works, so you can plan accordingly next time.


My estimate was close. I'll give myself an hour next week.  


When to Use Padding Time

Always. Seriously. 


When you’re scheduling your workday, estimate and pad.

When you’re planning chores, estimate and pad.

When you’re heading out to meet a friend, estimate and pad.


We're creating a buffer for things to go wrong, your kid to throw a tantrum, or a meeting to go 15 minutes over. 


Now I know…


A "quick trip to the grocery store" really takes 45 minutes. 

A "five-minute email" can easily turn into 15. 

My 3PM meeting with Suzanne will definitely run until 4. 


Summary 

Humans, and especially neurodivergent adults, struggle to accurately estimate how long tasks take. It’s due to weaknesses in our executive functions. It's also our natural instinct to overestimate how well things will go. 


Padding time is a simple strategy that improves our adult executive function skills and our ability to estimate how long something will take. 


Here’s how it works: 

  1. Select an important task.

  2. Estimate how long it will take. Then multiply by 1.5.

  3. Track how long it actually takes.

  4. Reflect and adjust for the future. 


When we pad time, we naturally manage our time more efficiently. We hit deadlines more often, are late less often, and have stronger relationships at work and home. 


If you really want to give this a try, send me an email with the name of this week's MIT and how long you estimate it will take. I’ll be your accountability partner and follow up with you at the end of the week. 


In service,

Eric



FAQs

Why do I always underestimate how long tasks will take?

Most people struggle with what psychologists call the planning fallacy—a natural bias that makes us underestimate how long, hard, or expensive something will be.


For neurodivergent adults with ADHD or autism, this problem is even more common.


Weaknesses in executive function skills like planning, sustained attention, and emotional regulation make it harder to predict time accurately. We tend to be overly optimistic about what our future selves can accomplish, forgetting about energy levels, distractions, or unexpected interruptions.

How can I get better at managing my time if I am neurodivergent?



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About the Author

adult executive function coaching

Eric Kaufmann is an Educational Therapist, Certified Executive Function Coach, and speaker. He is the Co-founder of UpSkill Specialists, an executive function coaching company that helps adults and workplace teams overcome disorganization, procrastination, and productivity roadblocks. Eric is also the founder of Elevate Learning Solutions, an Educational Therapy practice that supports neurodivergent students in becoming independent and confident. Book Eric to speak or lead a workshop.

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