A to-do list tells you what to do. It doesn't tell you when you'll be done, and that's usually where the day goes wrong: one task quietly takes the whole afternoon. Timeboxing is a simple fix. Before you start a task, you decide how much time it gets, and you work on it only inside that box.

What timeboxing is

You give each task a fixed length: 10 minutes for email, 45 for a report draft, 90 for a design review. Add the boxes up and your list turns into a plan with a finish time. If the plan ends at 21:00 and you wanted to stop at 18:00, you know at 9 in the morning, not at 5 in the afternoon.

The box is a limit, not a promise that the task will be finished. When time runs out you stop and decide: is it good enough, does it need another box, or should it move to tomorrow?

Here is a timeboxed morning, running on a loop: four boxes, each with its own length.

Timeboxing or pomodoro?

Both put a timer on your work, but they solve different problems.

  • Pomodoro uses the same rhythm for everything: 25 minutes of focus, a short break, repeat. It works well when your tasks are similar, like a day of studying one subject.
  • Timeboxing gives each task its own length. It works better when your tasks vary, like a 10-minute email and a 90-minute report on the same list.

You don't have to choose once. Many people timebox the day and use pomodoros inside a long box.

How to estimate a box

  • Start from what it took last time, not from what you hope. If the weekly report took 70 minutes last week, don't give it 30.
  • Split anything over two hours. "Write thesis chapter" can't be estimated; "outline section 2" can.
  • Leave room. Fill about 80% of the time you have. Interruptions and small jobs will use the rest.
  • Check at the end of the day. Compare planned and actual times. After a week you'll see which kinds of tasks you always underestimate.

Timeboxing your list in Todo & Timer

The timebox timer is free and runs in your browser, no sign-up needed.

  • Type the length into the task. "Write report 45m" or "Plan the week 1h30" sets the length as you add it. Tasks without one use your Default length.
  • See when you'll finish. The list adds everything up and shows the time you'll be done. Run it in order and each task starts after the last.
  • Time's up is a nudge, not a stop. When a box runs out you get a gentle reminder and the timer keeps counting on in grey. You decide when the task is done; nothing is ticked off for you.
  • Keep it in view. In Chrome and Edge, Pop out timer opens a small window that stays on top of your other apps.
  • Correct the forecast (Plus and Pro): once you've finished a few tasks, the finish time can be scaled by how long your tasks really take.

Prefer a fixed rhythm today? The same tasks work with the Pomodoro timer, and every round is recorded against its task.