How to Stop Underestimating How Long Tasks Take

Use your past, not your hope

Look at the last three times you did something similar. What did it actually take, start to finish? That number is your baseline, not the best-case version playing in your head.

Your memory edits out the friction — the false starts, the file you couldn't find. Real history includes all of it, which is exactly why it estimates better.

Apply a 1.5x multiplier as default

Most people underestimate by roughly 1.5x, so a 40-minute gut feel is usually a real hour. Multiplying your first number by 1.5 gets you close without much thinking.

It feels pessimistic the first few times. Then you finish on time for a week straight and it just feels accurate.

Add a buffer for the unknowns

Add another 25 to 50 percent for anything involving other people, new tools, or unfamiliar topics. Waiting on a reply or fighting a login screen is part of the task, not a separate event.

If you have ADHD and time blindness, this buffer matters even more — the gap between felt time and clock time tends to be wider, so estimate against the clock, not the feeling.

Estimate the whole, not just the work

Setup, breaks, context-switching, and review all count. For many tasks the actual work is barely half the total time on the clock.

Try this: write the task, then write everything around it. "Write the report" quietly includes finding last quarter's numbers, getting interrupted twice, and one read-through before sending.

Let a tool give you the honest range

Once you know the pattern, you can stop doing the math in your head. Mibbi Estimate takes your task and returns a realistic time range that includes the setup, the switching, and the friction most people forget.

So instead of "20 minutes" you get something like "35 to 55 minutes" — a number you can actually plan a day around.

FAQ

Does the 1.5x rule always apply?

Most of the time, yes. For routine tasks you have done dozens of times, it is closer to 1.1x. For genuinely new tasks, 2x or more is often the honest number.

Why do I keep underestimating even when I know I do it?

Because the optimism happens before you start, when the task is still abstract. The fix is structural — a default multiplier and a buffer — not willpower or trying harder to be realistic in the moment.