A pomodoro timer is two things at once, and most versions online only give you the second one. There is the planning half — how many focused sessions does this task actually need, and once the breaks are added, what time does that put me at? — and there is the running half, the clock counting down while you work. This page does both, because the first question is the one people get wrong.
Arb Digital keeps this in a free tools library used mostly for scheduling, estimating and measurement work, where the gap between "three hours of work" and "three hours on the calendar" causes real problems. A six-session block of twenty-five-minute pomodoros is two and a half hours of work but occupies more than three hours of your day. If you book the meeting after it on the basis of the first number, you will be late.
What This Pomodoro Timer Does
Enter your focus length, your two break lengths and how many sessions pass before a long break. Then either give the tool an estimate of how much focused work the task needs, in which case it converts that into whole sessions, or fix the number of sessions directly. It reports the sessions required, the total elapsed time once every break is included, how much of that elapsed time is break, and the clock time you finish if you begin at the start time you set.
The timer itself sits in the result panel. It opens showing the configured focus length as a ready state rather than a blank clock, so you can see your settings before committing to them. Press start and it counts the current phase down, then rolls automatically into the correct break — short or long depending on where you are in the cycle — and on into the next focus session. The skip button advances a phase without waiting, which is what you want when a session ends early or a break runs over.
The boundary with the closest tools already on the site is worth stating. The countdown timer runs a single interval to a moment you choose and has no concept of cycles or breaks. The exam countdown timer counts days to a fixed date rather than minutes within a session. The fasting timer tracks one long window rather than a repeating pattern. The time duration calculator measures the gap between two clock times and does no cycle planning. This page is the only one that builds a repeating focus-and-break structure and tells you where it ends.
How to Use It
- Set your interval lengths. Twenty-five and five are the classic figures, but nothing about the arithmetic depends on them, and longer intervals suit deeper work.
- Choose how to plan. Plan by work when you have an estimate in minutes; plan by count when you have a fixed block of time and want to know what fits.
- Check the elapsed figure, not the focus figure. The total with breaks is the number that belongs in your calendar.
- Set the start time to get a finish time. This is the fastest way to see whether a block fits before an existing commitment.
- Press start when you actually begin. The timer runs the cycle, rolling from focus into break and back without needing to be reset.
The Formula and How It Is Calculated
Sessions come first. When you plan by work, the session count is the focus work divided by the focus length, rounded up to a whole number, because a partial pomodoro is still an interval you have to sit through. One hundred and fifty minutes of work at twenty-five minutes per session is exactly six sessions.
Breaks are counted between sessions rather than after them. With n sessions there are n − 1 gaps, and a gap becomes a long break whenever the session that just ended completes a full cycle. Worked example with six sessions, a cycle of four, a five-minute short break and a fifteen-minute long break: the gaps sit after sessions one to five, the gap after session four is long, and the remaining four are short. Break time is therefore 4 × 5 + 1 × 15 = 35 minutes.
Total elapsed time is focus plus breaks: 6 × 25 + 35 = 185 minutes, or three hours and five minutes. Starting at 09:00 that finishes at 12:05. Notice that the breaks add 23% to the wall-clock cost of the block — that ratio is the single most useful output on the page, and it is the figure the bar chart shows.
Where the 25-Minute Figure Came From
The technique was developed by Francesco Cirillo in the late 1980s, named after the tomato-shaped kitchen timer he used as a student, and it is documented on the official Pomodoro Technique site, which describes it as a full productivity system rather than a timer — daily planning, interruption handling and effort estimation all sit inside it. The twenty-five-minute interval is a starting point in that system, not a scientific constant, and Cirillo's own material treats the length as something you adapt.
That matters because a great deal of writing about the technique presents twenty-five minutes as an optimum discovered by research. It was not. What research does support is the broader principle that frequent short breaks are more protective than rare long ones. NIOSH, the US occupational safety research institute, notes in its work on fatigue and work that fatigue accumulates with sustained demand and that break structure is part of managing it. That supports the shape of the method without endorsing any particular number of minutes.
The practical consequence is that you should treat the interval as a variable. Work that requires a long warm-up — writing, debugging, anything where you hold a lot of state in your head — often suits forty-five or fifty minutes better, because a twenty-five-minute interval spends a disproportionate share of itself reloading context. Work that is repetitive and easy to resume suits shorter intervals.
The Interruption Problem the Timer Cannot Solve
A pomodoro is defined as indivisible: if it is broken, it does not count and is restarted rather than resumed. That rule is the actual mechanism of the technique, and it is the part that a timer cannot enforce. The timer measures elapsed minutes; it has no idea whether you spent them on the task.
The original method handles this with a written record. Internal interruptions — the urge to check something — are noted on a list and dealt with in the break. External interruptions are negotiated: you tell the person when you will be free, which is usually within the current interval. The point is that both are recorded, so that after a week you can see how many pomodoros you lose and to what. Most people are surprised by the count.
If you find you cannot complete an interval without breaking it, the interval is too long for your current environment, not the other way round. Shorten it until you can complete one cleanly, then extend from there. A completed fifteen-minute session is worth more than an abandoned fifty-minute one.
Estimating in Sessions Instead of Hours
The quietly useful part of the method is that it changes the unit of estimation. "This will take about three hours" is a vague claim that is hard to check. "This is four pomodoros" is a specific claim that gets tested within the day, and after a fortnight you know whether your four-pomodoro estimates usually land at four, six or nine.
That feedback loop is what improves estimation, and it is why the planning half of this page exists. Enter the work you think a task needs, note the session count, and compare it against the sessions you actually spend. The gap is your personal estimation error, and it is usually stable enough to correct for — many people find they consistently need roughly half as many sessions again as they predicted.
When a task turns out to need more than about seven sessions, the standard guidance is to break it into smaller tasks, because an estimate that large is rarely accurate. When it needs less than one, group it with other small tasks so a single interval covers several of them. Both rules exist to keep the unit of work at a size you can actually judge.
Fitting Cycles Into a Real Day
The finish-time output exists because pomodoro blocks rarely sit in an empty calendar. If you have six sessions of work and a meeting at noon, starting at 09:00 gives you 185 minutes of cycle against 180 available, and you will overrun by five minutes. The tool shows that before you start rather than after.
Two adjustments usually fix an overrun without cutting work: shorten the long break, or move it. A long break placed immediately before an existing meeting is wasted, because the meeting is itself a break from the task. Setting the cycle length so that the long break lands somewhere useful is worth more than any change to the focus interval. For fitting a block into a working day around fixed commitments, the work hours calculator and the time card calculator handle the wider timesheet arithmetic, and the add subtract time calculator is quicker for a single one-off shift.
Arb Digital's free tools library covers the scheduling and estimating arithmetic behind marketing and delivery work, and our team is happy to talk through anything the tools cannot answer.
Browse Free Tools Talk to Arb DigitalCommon Mistakes to Avoid
- Booking the calendar on the focus figure — a six-session block of focus work occupies noticeably more wall-clock time once breaks are included.
- Resuming a broken session instead of restarting it — the indivisibility rule is the mechanism, and ignoring it turns the method into an ordinary timer.
- Treating twenty-five minutes as a law — it is the technique's starting point, not a measured optimum, and deep work often needs longer intervals.
- Working through the break — the break is what makes the next interval possible, and skipping it repeatedly is how the pattern collapses by mid-afternoon.
- Estimating tasks larger than about seven sessions — estimates at that size are usually wrong, and the task should be split before it is timed.
Related Free Tools From Arb Digital
Use the countdown timer for a single plain interval, the time duration calculator to measure the gap between two clock times, the work hours calculator for daily and weekly totals, the reading time calculator to estimate how long a document will take, and the exam countdown timer when the deadline is a date rather than a session. Everything else is in the free online tools hub.
Frequently Asked Questions
No. Everything runs in this browser tab and nothing is sent to a server or stored between visits, so closing the tab or navigating away clears the timer and the session count.
One fewer than the number of sessions, because breaks fall between sessions rather than after the last one. With six sessions there are five breaks, and each break is long or short depending on where it falls in the cycle.
Because the elapsed figure includes every break in the cycle. A block of six twenty-five-minute sessions is 150 minutes of focus but 185 minutes on the clock once four short breaks and one long break are added.
Yes, and the arithmetic does not depend on it. The figure is the technique's starting point rather than a measured optimum, and work with a long warm-up often suits longer intervals.
The method treats a pomodoro as indivisible, so an interrupted session is restarted rather than resumed. A timer cannot enforce that rule, which is why the original technique records interruptions in writing.
Planning by work takes an estimate in minutes and rounds it up to whole sessions. Planning by count fixes the number of sessions and reports how much focused work they cover, which suits a fixed block of available time.
Moving it is usually better than removing it. A long break placed just before an existing meeting is wasted time, so adjusting the sessions-before-long-break setting often recovers the overrun without cutting recovery.
This tool performs scheduling arithmetic and runs a timer in your browser. It is not a productivity or health assessment, and it makes no claim about how any individual should structure their working day.
