acalculator

What is the average time?

Type a list of times separated by commas. The average time calculator averages durations, such as lap, split or race times in h:mm:ss or m:ss, and gives the total, the shortest and the longest. Switch to times of day to average clock times such as bedtimes, even when some fall after midnight.

Your numbers

Average
Durations: 1:05:30, 5:12 or 45.5 (seconds). Times of day: 23:15 or 11:15 PM.
Average
0:05:11.25

The average is 0:05:11.25.

Average in seconds
311.25
Total
0:20:45
Times averaged
4
Shortest (or earliest)
0:05:05
Longest (or latest)
0:05:20

Average: 0:05:11.25. The average is 0:05:11.25.

How to calculate

Averages a list of times: durations such as lap or race times (h:mm:ss or m:ss), or clock times such as bedtimes, even across midnight, with the total, fastest and slowest.

Example with the default inputs (Average Durations, Times 5:12, 5:08, 5:20, 5:05): The average is 0:05:11.25.

Method: Durations: convert each to seconds (h × 3,600 + m × 60 + s), add, and divide by the count. Clock times: count each in seconds after the start of day (wrapping past midnight), average, and add the start back.

  • A duration of one number is seconds, two parts are m:ss, three are h:mm:ss; minutes and seconds after a colon are two digits, 00 to 59.
  • Clock times are averaged as times after the chosen start of day, so the answer depends on it; a noon start suits bedtimes.
  • Durations are summed in hundredths of a second; the average is rounded to the hundredth, and a clock-time average to the second.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Average Durations, Times 5:12, 5:08, 5:20, 5:05 gives Average 0:05:11.25, Average in seconds 311.25, Total 0:20:45, Shortest (or earliest) 0:05:05, Longest (or latest) 0:05:20.Source: The Python Standard Library, datetime: timedelta objects (durations add and divide exactly in microseconds), https://docs.python.org/3/library/datetime.html#timedelta-objects (retrieved 2026-10-02)
  2. Average Durations, Times 1:52:10, 1:48:35, 1:55:02 gives Average 1:51:55.67, Total 5:35:47.Source: The Python Standard Library, datetime: timedelta objects (durations add and divide exactly in microseconds), https://docs.python.org/3/library/datetime.html#timedelta-objects (retrieved 2026-10-02)
  3. Average Times of day, Times 11:00 PM, 1:00 AM, 11:30 PM, Day starts at 12:00 gives Average 11:50 PM, Shortest (or earliest) 11:00 PM, Longest (or latest) 1:00 AM.Source: The Python Standard Library, datetime: timedelta objects (durations add and divide exactly in microseconds), https://docs.python.org/3/library/datetime.html#timedelta-objects (retrieved 2026-10-02)
  4. Average Times of day, Times 8:15, 8:45, 9:10, Day starts at 00:00 gives Average 8:43:20 AM.Source: The Python Standard Library, datetime: timedelta objects (durations add and divide exactly in microseconds), https://docs.python.org/3/library/datetime.html#timedelta-objects (retrieved 2026-10-02)

How it works

Durations. Each entry is turned into seconds: a single number is seconds; m:ss is m × 60 + s; h:mm:ss is h × 3,600 + m × 60 + s. Seconds may have decimals.

  • each duration is rounded to whole hundredths of a second, and the hundredths are added, so the total is exact
  • average = total ÷ count, rounded to the nearest hundredth of a second (halves up)
  • shortest and longest are the smallest and largest entries
  • the average in seconds is total ÷ count ÷ 100 (hundredths to seconds), before rounding

Times of day. Each entry is a time after midnight, t, in seconds. With a start of day s (00:00 by default):

  • each time is counted as u = (t − s + 86,400) mod 86,400 seconds after the start
  • average = s + (the mean of u), wrapped into one day and rounded to the nearest second (halves up)
  • earliest and latest are the smallest and largest u, plus s

Rules

  • Entries are separated by commas, semicolons, new lines or spaces (a space before AM or PM belongs to the time). 1 to 1,000 entries.
  • Durations: digits, then up to two parts of exactly two digits from 00 to 59 after colons, then an optional decimal part. Each duration is at most 10¹⁰ seconds, so the total of 1,000 stays exact.
  • Times of day: h:mm or h:mm:ss with hours 0 to 23, or 1 to 12 followed by AM or PM (a.m. and p.m. also work, any case).
  • Anything else has no answer, and the message names the entry.

Output format. Durations read h:mm:ss, with .ss when the hundredths are not 0 ("0:05:11.25", "1:51:55.67"). Times of day read as 12-hour clock times, h:mm AM or PM, with :ss when the seconds are not 0 ("11:50 PM", "8:43:20 AM"; midnight is 12:00 AM).

Worked examples by hand

Splits 5:12, 5:08, 5:20, 5:05. 312 + 308 + 320 + 305 = 1,245 s = 0:20:45; ÷ 4 = 311.25 s = 0:05:11.25. Shortest 0:05:05, longest 0:05:20.

Races 1:52:10, 1:48:35, 1:55:02. 6,730 + 6,515 + 6,902 = 20,147 s = 5:35:47; ÷ 3 = 6,715.67 s = 1:51:55.67.

Bedtimes 11:00 PM, 1:00 AM, 11:30 PM, day from noon. After noon: 11 h, 13 h and 11 h 30 min; mean 11 h 50 min, so 11:50 PM. Earliest 11:00 PM, latest 1:00 AM.

8:15, 8:45 and 9:10, day from midnight. 29,700 + 31,500 + 33,000 = 94,200 s ÷ 3 = 31,400 s = 8:43:20 AM.

Other questions people ask

How do I average times?

Turn each time into seconds, add them up, divide by how many there are, and turn the result back into hours, minutes and seconds. Splits of 5:12, 5:08, 5:20 and 5:05 are 312 + 308 + 320 + 305 = 1,245 seconds; ÷ 4 = 311.25 s = 5:11.25.

How do I type the times?

Separate the times with commas or spaces. Durations can be h:mm:ss (1:52:10), m:ss (5:12) or plain seconds (45.5), with decimals of a second if you need them. Times of day can be 24-hour (23:15) or 12-hour (11:15 PM).

How do I average times that cross midnight?

Count each time from a start of day before midnight. With the day starting at noon, 11:00 PM is 11 hours later and 1:00 AM is 13 hours later; their average, 12 hours, is midnight, not noon. Choose times of day and set the day start to 12:00 for bedtimes.

Why does the start of day matter?

A clock wraps around every 24 hours, so "the average of 11 PM and 1 AM" has two candidates, midnight and noon. Counting from a start of day picks one; noon suits night-time events and midnight suits daytime ones.

How do I find an average lap time?

Type each lap time. The average is the total time divided by the number of laps. If you know only the total, divide it by the lap count: 20:45 over 4 laps is 5:11.25 a lap.

How precise is the answer?

Durations are added in hundredths of a second, so typed decimals do not drift, and the average is rounded to the hundredth. Averages of clock times are rounded to the second.