Chronic lateness with ADHD is rarely about priorities. It usually comes from three specific miscalculations: preparation time is not counted, transition time is not counted, and the last task before leaving expands without being noticed.
This matters because lateness is read socially as a statement about how much you value the other person. That reading is what makes it so corrosive, and it is usually wrong.
The three miscalculations
Travel time is treated as total time
The journey is twenty minutes, so leaving at 9:40 for a 10:00 meeting seems right. But the actual sequence is: stop what you are doing, find keys, shoes, coat, bag, check you have everything, walk to the car, then twenty minutes. The genuine cost is closer to thirty-five, and only twenty of it was counted.
The transition out is not counted at all
Stopping the current task is itself an operation, and it takes time — often five to ten minutes of finishing the thought, saving the thing, closing the loop. If you plan to leave at 9:40 and start disengaging at 9:40, you leave at 9:50.
“One quick thing” before leaving
The available margin invites one more small task. Because short tasks are systematically under-estimated, the three-minute thing is eleven minutes, and the margin is gone. This is the most common single cause.
Why it persists despite genuine effort
Underneath all three is unreliable duration estimation and a weak felt sense of approaching time. Barkley’s model, summarised by CHADD, Executive Function Skills, places the sense of time inside nonverbal working memory. Without a reliable background signal that a deadline is closing in, the approach is not felt building — it is only noticed on arrival.
Which is why the experience is so often: comfortable, comfortable, comfortable, catastrophically late. There was no gradient.
What actually works
Plan to arrive early, not to leave on time
Target arriving fifteen minutes early. This is not the same as leaving fifteen minutes earlier — it changes what you are optimising, and the buffer absorbs the errors above.
Set the alarm for stopping, not for leaving
An alarm at 9:40 labelled “leave” arrives when you should already be at the door. Set it at 9:25 labelled “stop what you are doing.” The transition needs its own trigger.
Use two alarms
One to stop, one to actually go. The second catches the case where the first was absorbed into whatever you were doing.
Stage everything the night before
Keys, bag, shoes, coat by the door. Every item you have to locate in the morning is a potential five-minute search, and searches are where margins die.
Ban the last task
A firm rule that nothing new starts after the stop alarm. Not one email, not one dish. This rule alone resolves a substantial share of chronic lateness.
Make waiting bearable
Arriving early is only sustainable if the early time is not aversive. Have something to do — a book, audio, anything. People who find waiting intolerable will unconsciously stop arriving early, so solving the waiting problem is part of solving the lateness problem.
Common questions
Why am I late even for things I want to attend?
Because the mechanism is estimation and transition, not motivation. Enthusiasm does not correct arithmetic.
Why does setting clocks fast stop working?
Because you learn the offset and mentally subtract it. Anything you can correct for stops functioning.
How do I explain it without sounding like I am making excuses?
Pair the explanation with the fix. “I under-count preparation time, so I now set a stop alarm fifteen minutes earlier” is a plan. The explanation alone, repeated, stops being persuasive.
Related reading
Sources
- CHADD, Executive Function Skills — Barkley’s nonverbal working memory and sense of time
Inchy publishes general information, not medical advice. Difficulty with attention, time, and task initiation has many possible causes. If it is affecting your work, health, or relationships, speak to a qualified clinician who can consider your full situation. See our editorial policy.