01What this calculator does
This calculator reports the average of a set of time durations. On the left, paste in a list of time durations, one per line. The results are reported on the right. The calculator reports the mean of the times, the running total of the times, the number of times, the smallest time, the largest time, and the range of the times. This calculator works with time durations entered in the format h:mm:ss, mm:ss, or as plain numbers mixed together, so you do not need to pre-sort or reformat your list of times.
This is designed as a lap/split time calculator (for running or other activities) to display your average mile time (or 5K time) based on an average of all the times of laps or splits you entered. But this can also be used to compute an average based on a list of work-shift lengths, a list of task or call lengths, or even a list of cook times. And if you need to compute an average of simple numbers (e.g. heights and weights), there is a Body Mass Index (BMI) calculator and a conduit fill calculator at this site to compute other average values that are commonly needed in everyday activities.
02Time formats you can enter
Values with colons are read from the right, i.e. as hours, minutes and seconds. Values without a colon are read as seconds by default. But you can switch this in the dropdown for the column, to read them as minutes, should your data be a simple list of values like 90, 105, 120 in this example. This is how you would read the table values.
03Where averaging times is useful
Averaging the duration of time it takes to complete things (or measurements, or readings of some sort) can create a meaningful average from a bunch of varied pieces of data. Runners may average their splits to find their pace during a race. A store or restaurant manager may average the duration of time of each of the staff’s shifts or the amount of time it takes for them to handle a customer. National statistical agencies report averages of the amount of time individuals spend in daily activities, even reporting it down to the minute for the annual time-use release. For example, the U.S. Bureau of Labor Statistics’ American Time Use Survey reports the average amount of time people spend on various daily activities.
Also note that the Census Bureau tracks the average commuting time to work using a similar method, which is reviewed in university statistics classes as a measure of central tendency — the mean. To find the difference in two people’s ages, use the age gap calculator instead.
Behind the scenes, the basis for each entry is changed to seconds. That way everything can be added up without the classic problem of averaging the hours, minutes and seconds columns separately, which won’t work once the minutes or seconds hit 60. The times are summed in seconds, then divided by the count to get the average in seconds, and only the final answer is converted back to h:mm:ss for display.
As time is measured in seconds, (as defined by the NIST Time and Frequency Division using an atomic clock) seconds are the natural common unit. The average is rounded to the nearest second, while average in seconds is calculated to one decimal place to show the exact result.
- Durations, not times of day. Enter elapsed time (how long something took), not a clock reading. To average clock times that wrap past midnight you need circular statistics, which this calculator does not do.
- The mean is pulled by outliers. One very slow lap drags the average up. The shortest, longest and range are shown so you can spot a value that is skewing the result.
- Equal weighting. Every entry counts the same. If some durations represent more work or distance than others, a weighted average would be more accurate.
- Colons mean h:m:s. A two-part value like 1:30 is read as one minute thirty seconds, not one hour thirty. Add a third field — 1:30:00 — when you mean hours.
01The average time formula
Averaging times is the arithmetic mean applied to durations. The only twist is that you must put every duration into one common unit before you add, then convert the answer back.
Where:
- t₁ … tₙ= each individual duration in the set.
- n= the number of durations (the count).
- s= the total, or the average, expressed in seconds.
- ⌊ ⌋= the floor function — round down to the whole number.
02Worked example
Say a runner logs three mile times — 7:15, 7:45 and 8:10 — and wants the average pace. Work each unit separately, exactly as you would by hand:
Average mile pace is 7:43 or 463.3 seconds. The leading tools use a count → sum → divide method to compute the average and that is exactly what the arithmetic mean (measure of center) is. One would only need to translate to and from seconds.