# Time blocking: how to plan your day in hours, not lists

> Give every task a slot in your calendar instead of a line on a list. How time blocking works, why it helps, how to run a day, and when to skip it.

Source: https://priortasks.com/guides/time-blocking/
Last updated: 2026-11-05

Time blocking means giving each task a slot in your calendar, with a start and an end, instead of leaving it on a list. A to-do list says what you want to do. A time-blocked day says when, and shows you at once whether it fits.

## Where it comes from

Cal Newport, a computer science professor and the author of *Deep Work* (2016), made the routine well known. In a [blog post from December 2013](https://calnewport.com/deep-habits-the-importance-of-planning-every-minute-of-your-work-day/) he describes planning every minute of the workday on one sheet of paper. Each evening he writes the next day as blocks with a named task in each, and he leaves room beside every block to correct it when the day does not go as planned. He later published a paper planner built on the idea, *The Time-Block Planner*.

## Why it works

Little research tests time blocking under that name. The case rests on three findings about planning and attention.

**A list hides the size of your day.** People underestimate how long their own tasks take. In a 1994 study by Roger Buehler, Dale Griffin and Michael Ross (*Journal of Personality and Social Psychology*), 37 psychology students predicted that their senior thesis would take 33.9 days on average. It took 55.5 days, and about 30% finished when they had predicted. Daniel Kahneman and Amos Tversky named this the planning fallacy. A block puts your estimate next to your meetings and lunch, where the hours are visible and limited.

**A time turns an intention into a plan.** Peter Gollwitzer and Paschal Sheeran's 2006 meta-analysis of 94 tests found that plans saying when and where you will act helped people reach their goals more than setting the goal alone, in most of the comparisons (d = .65, a medium-to-large effect). A block is not exactly the "if-then" plan they studied, but it fixes the same thing: Tuesday at 10:00, you write the proposal.

**Switching costs attention.** In two experiments, Sophie Leroy (*Organizational Behavior and Human Decision Processes*, 2009) found that people who moved to a new task while the last one was unfinished kept thinking about it and did worse on the new one. She called it attention residue. A block with one task, ended on purpose, gives you fewer half-finished switches.

## How to run a day

1. **Block what is already fixed.** Meetings, lunch, school runs, travel.
2. **Size each task.** Write your best guess in minutes. Then compare your guesses with last week: if you usually run over, add time.
3. **Put the demanding task in your best hours.** Notice when you think best, and use that stretch for the work that needs the most thought.
4. **Batch the small things.** Messages, invoices and quick calls go in one block of their own.
5. **Leave gaps.** A few minutes between blocks, and a block for the unexpected.
6. **When the day slips, redraw the rest of it.** Move blocks, drop the least important one. Do not carry on as if nothing happened.

A day for a freelancer could look like this:

| Time | Block |
| --- | --- |
| 09:00 to 09:30 | Plan the day, answer urgent messages |
| 09:30 to 11:30 | Write the client proposal |
| 11:30 to 12:00 | Buffer |
| 12:00 to 13:00 | Lunch |
| 13:00 to 14:00 | Client call |
| 14:00 to 14:45 | Invoices and admin |
| 14:45 to 15:00 | Break |
| 15:00 to 16:30 | Design review for project B |
| 16:30 to 17:00 | Messages, then plan tomorrow |

The proposal sits in the morning because it needs the most thought. The small tasks are batched. The buffer absorbs a call that runs long.

## Mistakes to avoid

- **No slack.** A day with no gaps breaks at the first delay, and then you stop trusting the plan.
- **Treating the plan as a promise.** It is a draft. Newport himself leaves space to rewrite it.
- **Giving every task the same length.** Size them, or the blocks mean nothing.
- **Planning work and forgetting breaks and lunch.** They take real time, and skipping them costs you later in the day.
- **Never comparing plan and result.** At the end of the week, look at where you ran over. That is how your estimates get better.

## When it is the wrong tool

- **When your day is mostly reactive.** Support, on-call and a busy shop cannot be planned minute by minute. Newport suggests blocking open-ended time for reacting, and keeping a small block at the edge of the day for deeper work.
- **When your hours belong to someone else.** If a rota decides your day, there is little to place.
- **When a missed block feels like failure.** If a rigid plan makes you anxious, use a looser list for a while.
- **For tiny tasks with no duration.** Batch them into one block instead of planning each.

## In Prior

> [!pro] Automatic planning is part of Pro
> Without Pro you can still block time by hand: create an event in the **Calendar** for each block. **Settings → Planning** also shows your week as Prior would plan it, and any time you locked earlier keeps showing on Today and in the calendar. [Plans and pricing](https://priortasks.com/docs/account/plans-and-pricing/) has the details.

With Pro, Prior blocks the time for you. It reads your open tasks, your calendar and your settings, then places each task in a free working hour around your meetings. It is on by default; the **Plan my tasks** switch in the Calendar turns it off and on.

What it uses and what you see:

- **Your tasks.** Priority and due date decide the order. The length comes from **Estimated time (minutes)** on the task. Without one, Prior AI estimates it, or a guess from the title, the checklist and the description does, with 30 minutes as the default. Your own estimate always wins.
- **Today.** The **Your plan** card lists the blocks left for today, with planned and free time.
- **Calendar.** Planned blocks are hatched. Blocks you locked are solid with a lock. A banner warns when tasks may miss their deadline or found no free time.
- **Your settings.** In **Settings → Planning**, **Your week** redraws as you change anything. Under **Your rhythm** you set working days and hours, lunch, **When I work best** (morning, afternoon, evening or no preference) and **How full should my days be?**. Light plans up to 4 hours of tasks a day, Balanced 6 and Full 8. Each calendar has a **Counts as busy** switch.

To make a block real, open it and choose **Keep this time**. The time is saved on the task and Prior plans around it. You can also drag a block in the day or week view, and resizing it changes the estimate. **Let Prior choose the time** gives it back, and **Not today** moves it to the next working day.

Prior replans when tasks, the calendar or the settings change, and every 5 minutes, so a missed block moves forward. The block in progress and the ones starting within 30 minutes stay put. It never moves your calendar events and never writes to Google Calendar, which it only reads.

Read more in [Time blocking](https://priortasks.com/docs/planning/time-blocking/), [Planning settings](https://priortasks.com/docs/planning/planning-settings/) and [Lock a block](https://priortasks.com/docs/planning/lock-a-block/). Pair it with the [Pomodoro technique](https://priortasks.com/guides/pomodoro-technique/) to work inside a block.