A one-hour meeting does not cost one hour

Ten o’clock, one-hour meeting. On your calendar it takes one slot, and a slot feels manageable. An hour is not much.

Except that at 9

you are already thinking about what you will say. At 10 the discussion drifts onto a topic nobody planned for, and you take notes hoping to come back to it. At 11 you leave with three action items, one open question and the feeling that your morning has melted. You get back to work at 11 with a half-written draft in your head, and there is not enough time left to finish it before lunch.

The calendar showed sixty minutes. Your morning lost more than that. This sum is almost never done when people plan their week, and it is worth doing once, with the numbers that exist.

Your calendar only sees the slot

A calendar records a start time and an end time. It does not see what comes before the meeting or what follows it. Yet a meeting has three parts.

The first is warm-up. Even when you have nothing to prepare, part of your attention turns toward the meeting in the minutes before it: you reread the invite, guess what they will ask, open files you never touch.

The second is the meeting itself. It is the only part your calendar shows.

The third is the aftermath: the decisions to write down, the message to send, the person to chase. It is the heaviest part and the least visible.

That third part has been studied. In 2009, researcher Sophie Leroy showed that when you leave a task unfinished, part of your mind keeps working on it while you do the next one. In her two experiments, people who moved to a new task without finishing the previous one performed worse on the new task. A meeting that ends with “let’s come back to this” closes nothing. It leaves open a task you did not choose, and you carry it into your next block.

The split morning

The real cost is often geometric. A meeting from 10

to 11 does not take an hour out of your morning. It cuts the morning in two. Before it, from 9 to 10, is a slot too short for demanding work, especially when that work needs a warm-up. After it, from 11 to 12, is a slot that starts with the residue of the meeting.

You can have three free hours in a day and never have one that runs unbroken. For writing, analysis or code, that unbroken block is exactly what matters: a stretch where you can keep the whole problem in your head. A forty-minute gap is good for answering messages, not for drafting a section.

Take a realistic case. You blocked two hours, from 9

to 11, to write a proposal. At 10 a thirty-minute meeting lands in the middle. You get half an hour before it, spent getting back into the subject, and half an hour after it, spent replaying what was said. You reserved two hours and you may use forty minutes of them. Nothing visible disappeared, and the block still did not hold.

The numbers: what Microsoft measures in its customers

In June 2025, Microsoft published a follow-up to its Work Trend Index, based on telemetry from people who use Microsoft 365. These are not figures from a sample representative of all employees, and the company has an interest in showing how central its tools are to work. Still, they are behavioural measurements, not self-reported memories, and they describe something you will recognise.

Three figures matter here. Half of all meetings take place between 9 and 11 a.m. or between 1 and 3 p.m., exactly the windows when many people are most alert, and exactly where meetings tend to land. Then 57% of meetings are ad hoc calls with no calendar invite, so they never appear in your planning; they simply arrive. Finally, on average these users are interrupted every two minutes during core working hours, by a meeting, an email or a notification.

The same report points to two trends that make the split worse. Meetings starting after 8 p.m. rose 16% year over year, and close to a third of meetings now span several time zones. The evening spills into the next day, and each time slot has more constraints to fit.

The first figure explains why your morning is already taken by someone else. The second explains why you do not see the day fragmenting. The third explains why a meeting cannot be judged alone: it is added to a flow that is already cut up.

A reply worth keeping in your mail client

I am not suggesting you decline every meeting. I am suggesting one reply, always the same, to any invitation whose purpose is unclear. Here is the one I recommend:

Thanks for the invite. To make the hour worth it, could you tell me in one line which decision you need from me? If it is information, a short message or a five-minute recording will do, and I will read it in my next focus block.

Keep it within reach. Save it as a template in your mail client, or as a snippet in a text expander if you use one on Windows. Then use it whenever an invitation does not name a decision.

It does two things. You read the purpose before you accept, which does not happen when you click “accept” out of reflex. And the job of stating the objective goes back to the person who sent the invite. If the reply is slow or vague, you have your answer: there may not have been a decision to make.

Two mistakes that keep coming back

The first is accepting to avoid friction. A meeting is rarely justified by its content. People accept so they do not seem distant, so they do not upset the organiser, so they stay “in the loop”. Those reasons are human. They say nothing about what the meeting costs your output. Accepting without reading the purpose means deciding on behalf of your time.

The second is staying “available”. You answer messages quickly between meetings and do not start a deep block because the next call might move up. By the end of the week, there is no stretch of work left, only pieces of replies.

[ANECDOTE DIANE: a morning you lost this way, what you did next, and what you would do differently.]

When the meeting is worth its cost

It would be wrong to decline everything. A meeting is justified when writing does not do the job: a disagreement to settle, a negotiation, a decision among several people where each needs to hear the others’ reservations. In those cases a split morning is a reasonable price, because the result cannot come out of a message.

The test I suggest is one question. If you need to hear a reaction and discuss it, the meeting earns its slot. If you only need the information to exist somewhere, it does not. This is not a grid to fill in. It is a question to ask while reading the invitation, before you reply.

Freelancers and people who handle clients are a special case. They cannot refuse a client call, but they can decide where it goes. One fixed slot in early afternoon, announced once, protects the rest of the day: clients learn when to call, and unplanned calls become the exception.

What actually protects your morning

The reply template filters what comes in. It does not protect the block. For the block, I hold to one simple rule: the first meeting of the day never lands in your best deep-work slot. If it has to be scheduled, move it after the block. This is not about comfort. It is the only way to keep one morning stretch intact when other people’s calendars keep pushing.

If you already block your calendar, the same logic applies. A protected slot holds as long as it is written down, and it disappears as soon as it stays a wish. Timeboxing that survives Tuesday explains how to keep those blocks standing until the following week.

One more detail. Deep work does not need the whole day. A well-protected ninety-minute block does more than a morning cut into twenty pieces. The rest, such as messages, fits into two or three passes through the day rather than a continuous drip.

My view

A meeting under fifteen minutes with no agenda is almost always a badly written message. I hold that without reservation for information updates. For hard decisions I am more careful: a good discussion can be worth an hour, but only if someone has prepared it.

What this changes for you

The next invitation without a purpose already has its answer. And next time you look at your calendar, count the free stretches, not the hours. A day is judged by its unbroken blocks.

If the meeting already starts with ten minutes of audio settings and broken links, your video call loses five minutes before it even starts covers that startup and a routine to shrink it. To understand what happens when you leave a task before finishing it, read the time you sell without noticing. And if meetings have taken over your week, the lesson Effective Meetings gives the full method for deciding, shortening or turning each one into writing.

Sources

Figures and quotes checked on 5 November 2026. Microsoft’s data covers its Microsoft 365 users and is published by the company itself.

See the 2 sources for this article

• Microsoft WorkLab, 17 June 2025, Breaking down the infinite workday
• Sophie Leroy, 2009, Why is it so hard to do my work? The challenge of attention residue when switching between work tasks, Organizational Behavior and Human Decision Processes