I often have to generate a sequence of clock times so I created this simple online utility that does it for me. It lets you generate however many clock times you need starting from any o'clock with any time interval between the times. It works in the browser and is powered by alien technology from the future.

Clock Time Generator Options

Start, Interval, and Count
Output Format
Clock time format.
Toggle between 24-hour and 12-hour clocks.
Append am/pm indicator after the time.
Hour, Minute, Second Base

Clock Time Generator Examples (click to try!)

Five-second Time Interval
In this example, we generate a time series with 13 equally-spaced clock times that have a five-second interval between them. We start at midnight (00:00:00) and increase each next time by 5 seconds. Thirteen output values give us a time range of one minute that ends at 00:01:00. We use the standard two-digit notation "hh:mm:ss" and display each time on a new line.
00:00:00
00:00:05
00:00:10
00:00:15
00:00:20
00:00:25
00:00:30
00:00:35
00:00:40
00:00:45
00:00:50
00:00:55
00:01:00
Start time (hh:mm:ss).
Interval between times.
How many clock times to generate?
Use am/pm Symbol
Use 12 Hour Clock
Separate output time values with this character. (Newline by default.)
Decimal Base
Generate Increasing Time
One Hour, One Min, One Sec
In this example, we start the time at 01:01:01am o'clock, set the delta interval to 01:01:01 (1 hour, 1 minute, and 1 second), and generate a list of 60 time values. This list spans multiple days but as we can only output clock times and not calendar dates, we only see alternating am and pm indicators every 12 hours. To be more precise, the interval covers 60 hours and 1 minute, which is 2 days, 12 hours and 1 minute.
01:01:01 am, 02:02:02 am, 03:03:03 am, 04:04:04 am, 05:05:05 am, 06:06:06 am, 07:07:07 am, 08:08:08 am, 09:09:09 am, 10:10:10 am, 11:11:11 am, 12:12:12 am, 01:13:13 pm, 02:14:14 pm, 03:15:15 pm, 04:16:16 pm, 05:17:17 pm, 06:18:18 pm, 07:19:19 pm, 08:20:20 pm, 09:21:21 pm, 10:22:22 pm, 11:23:23 pm, 00:24:24 am, 01:25:25 am, 02:26:26 am, 03:27:27 am, 04:28:28 am, 05:29:29 am, 06:30:30 am, 07:31:31 am, 08:32:32 am, 09:33:33 am, 10:34:34 am, 11:35:35 am, 12:36:36 am, 01:37:37 pm, 02:38:38 pm, 03:39:39 pm, 04:40:40 pm, 05:41:41 pm, 06:42:42 pm, 07:43:43 pm, 08:44:44 pm, 09:45:45 pm, 10:46:46 pm, 11:47:47 pm, 00:48:48 am, 01:49:49 am, 02:50:50 am, 03:51:51 am, 04:52:52 am, 05:53:53 am, 06:54:54 am, 07:55:55 am, 08:56:56 am, 09:57:57 am, 10:58:58 am, 11:59:59 am, 01:01:00 pm
Start time (hh:mm:ss).
Interval between times.
How many clock times to generate?
Use am/pm Symbol
Use 12 Hour Clock
Separate output time values with this character. (Newline by default.)
Decimal Base
Generate Increasing Time
Clock Times in Hex
In this example, we use a hexadecimal base to generate a sequence of clock times with 30-minute increments. We start from the value 9:0, which is a short version of 09:00am and calculate the next 15 values. We use single-digit hours and minutes for the output and separate all times with the pipe symbol. Just for your information, numbers 10, 11, 12, 13, 14, 15, and 16 are a, b, c, d, e, f, and 10 in hex. So the time 10:00 in hex is 0a:00 (or a:0 for short) and 10:30 is 0a:1e (a:1e for short).
9:0 | 9:1e | a:0 | a:1e | b:0 | b:1e | c:0 | c:1e | d:0 | d:1e | e:0 | e:1e | f:0 | f:1e | 10:0
Start time (hh:mm:ss).
Interval between times.
How many clock times to generate?
Use am/pm Symbol
Use 12 Hour Clock
Separate output time values with this character. (Newline by default.)
Hexadecimal Base
Generate Increasing Time
All Hours of the Day
In this example, we set the starting time to 0 (which is a short-hand notation for 00:00am), the time step to 1h, and run through a full day of hours. We use a 24-hour clock and output all hours from 0 to 23 in a single-digit format, together with an am/pm indicator at the end.
0 am, 1 am, 2 am, 3 am, 4 am, 5 am, 6 am, 7 am, 8 am, 9 am, 10 am, 11 am, 12 am, 13 pm, 14 pm, 15 pm, 16 pm, 17 pm, 18 pm, 19 pm, 20 pm, 21 pm, 22 pm, 23 pm
Start time (hh:mm:ss).
Interval between times.
How many clock times to generate?
Use am/pm Symbol
Use 12 Hour Clock
Separate output time values with this character. (Newline by default.)
Decimal Base
Generate Increasing Time
Counterclockwise Time
This example generates time that runs counterclockwise. It prints clock time every 600 seconds, starting at 9am and going in reverse order. It calculates 37 values that end early in the morning at 3am. As the delta of 600 seconds is exactly 10 minutes, the time decreases by one hour every sixth time. It uses the HH:MM time format and separates the values by a semicolon.
09:00 am; 08:50 am; 08:40 am; 08:30 am; 08:20 am; 08:10 am; 08:00 am; 07:50 am; 07:40 am; 07:30 am; 07:20 am; 07:10 am; 07:00 am; 06:50 am; 06:40 am; 06:30 am; 06:20 am; 06:10 am; 06:00 am; 05:50 am; 05:40 am; 05:30 am; 05:20 am; 05:10 am; 05:00 am; 04:50 am; 04:40 am; 04:30 am; 04:20 am; 04:10 am; 04:00 am; 03:50 am; 03:40 am; 03:30 am; 03:20 am; 03:10 am; 03:00 am
Start time (hh:mm:ss).
Interval between times.
How many clock times to generate?
Use am/pm Symbol
Use 12 Hour Clock
Separate output time values with this character. (Newline by default.)
Decimal Base
Generate Decreasing Time
Five Days
This example sets the time interval step to 12 hours and prints 10 time values in the output. Every two values a new day begins and as it uses a 12-hour clock, the time switches between 08:08:08am and 08:08:08pm. If it used a 24-hour clock, the time would switch between 08:08:08 and 20:08:08 (as 8pm is 20:00).
08:08:08 am
08:08:08 pm
08:08:08 am
08:08:08 pm
08:08:08 am
08:08:08 pm
08:08:08 am
08:08:08 pm
08:08:08 am
08:08:08 pm
Start time (hh:mm:ss).
Interval between times.
How many clock times to generate?
Use am/pm Symbol
Use 12 Hour Clock
Separate output time values with this character. (Newline by default.)
Decimal Base
Generate Increasing Time

How Does This Clock Time Generator Work?

This linear time series generator works entirely in your browser and is written in JavaScript. It starts by validating and parsing the given start and interval time values. It uses four different regular expressions to test the correctness of the input time. The first regexp is /(\d{1,2}):(\d{1,2}):(\d{1,2})/ that matches the HH:MM:SS and H:M:S time format that includes hours, minutes, and seconds. The second regexp is /(\d{1,2}):(\d{1,2})/ that matches the HH:MM and H:M time formats that includes hours and minutes. The third regexp is just /(\d+)/ that matches seconds. The fourth regexp is /(\d{1,2})\s*(am|pm)/i that matches the 12-hour clock time format. If the time format is correct, then it converts both time values to seconds as it's easier to do the time arithmetic in seconds. The start time is stored in the startInSeconds variable and the delta in the intervalInSeconds variables. To calculate just the seconds from hours, minutes and seconds, it uses the formula hours*3600 + minutes*60 + seconds. To generate count (specified in options) time values in the output list, it runs a for loop count times. The loop starts by assigning the startInSeconds value to the variable currentTimeInSeconds and in every iteration adds (or subtracts, if time is generated in reverse) the intervalInSeconds step value to the currentTimeInSeconds value, and saves this number in the output list outputTimes. After that, it turns the saved seconds back to hours, minutes, and seconds. This is done by using the inverse function of the formula above. To convert the 24-hour time format to the 12-hour format, the after-the-noon hour values get 12 subtracted from them. The output formatting is performed by using the String.replace() function. The output format values HH and H get replaced by the numeric hours, MM and M get replaced by the numeric minutes, and SS and S get replaced by the numeric seconds.

Created by Browserling

This clock time generator was created by me and my team at Browserling. Behind the scenes, it's actually powered by our programmer tools that are used by millions of people every month. Browserling itself is an online cross-browser testing service powered by alien technology. Check it out!

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