# Clock time decrementer

World's simplest time tool
With this browser-based application, you can subtract any time interval from the given clock time. The time interval to be subtracted can be any hours, minutes, and seconds (specified in the options). The decremented time can be output in various formats (24-hour clock, 12-hour clock, text, or seconds) and if the clock goes back too much, you can control the time underflow using four underflow modes. Created by computer nerds from team Browserling.

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## What is a clock time decrementer?

learn more about this tool
This is a quick online utility for decrementing one or more clock times by any time amount. When time is decremented, the clock moves backward. There are many use-cases for this time operation. For example, if you had a great workout and recorded great sprint times but then noticed that there was a stopwatch measurement error of two seconds, then you can quickly and effortlessly subtract these 2 seconds from each recorded time. Another great use-case is making DST adjustments when the clock is moved back by one hour. Overall, you can subtract any number of seconds, minutes, and hours from a clock time (or multiple clock times). The interval that needs to be subtracted can be set in the options using several different formats. For example, the interval can be "2 hours", "5 minutes", "30 seconds", "1h 2m 3s", "8 hours 2 min", or "5:10:02". Each time to be decremented must be listed in the input field, one per line. You can use full or partial 24-hour and 12-hour time formats in the input. For example, good inputs are "20:30:00", "20:30", or "10:30 pm". When the time is shifted backward, it will appear in the output field. You can choose from a variety of time formats for the output, and display the time as a digital clock (24-hour and 12-hour formats), in absolute number of seconds, or as spelled text. A separate option can be used to control the scenario when time underflows. Underflow happens when you decrease midnight time by 1 second (or more). For example, if the current time is 00:00:05 (5 seconds past midnight) and you decrease this time by 10 seconds, then you'll get the previous day 23:59:55. The "Print Strict Time" underflow method will print "23:59:55". You can also mark the previous day (or days) via the "Mark Time Underflow" underflow method and you will get "23:59:55 (-1)". The "minus 1" here indicates that day changed by one day backwards. You can also enable negative time with the "Print Non-strict Time" method. Here, the new time will be printed with a minus sign and you'll get "-00:00:05". Finally, if you want the time to stop at midnight "00:00:00", use the "Stop Time at Midnight" method. If instead of decrementing time, you need to increment time, use our increment clock time program. Timeabulous!

## Clock time decrementer examples

Click to useSet Clocks Back by One Hour

In this example, we switch to wintertime and set all clocks back by one hour. In the options, we enter the interval equal to "1 hour" and activate the "Print Strict Time" option so that the time that's close to 00:00:00 keeps decreasing from 23:59:59.

10:20:30
06:00:00
20:50:00
14:40:04
00:30:00

09:20:30
05:00:00
19:50:00
13:40:04
23:30:00

**Required options**

Set the decrement interval.

Decrement 12-hour Time

In this example, we load a list of clock times in a 12-hour format and subtract 2 hours and 40 minutes from them. Since we have a non-strict time mode selected, times that underflow 00:00:00 become negative.

2 am
5 am
8 pm
10:40 am
9:45:50 pm

-0:40:0 am
2:20:0 am
5:20:0 pm
8:0:0 am
7:5:50 pm

**Required options**

Set the decrement interval.

Decrease the Time by More than a Day

In this example, we decrement the given time values by 25 hours, which is equal to one day and one hour. By subtracting such a large time interval, many of the time values underflow the midnight point (00:00:00). When such underflow happens, the day changes to one day in the past. To see how many days have passed, we activate the "Mark Time Underflow" mode, which shows in the parentheses how many days in the past each time ends up.

00:00
06:00
12:00
24:00
32:00

23:0:0 (-2)
5:0:0 (-1)
11:0:0 (-1)
23:0:0 (-1)
7:0:0

**Required options**

Set the decrement interval.

Decrease Time Within One Day

In this example, we shift several times backward by a custom interval and we disallow the times to be shifted beyond the boundaries of a single day. In other words, when the time reaches 00:00:00, the time freezes and no longer decreases. We shift all clocks back by 9 hours, 39 min, and 59 secs and to make it easier and quicker to write this interval in the options, we use the digital clock interval format "09:39:59" for it.

04:30:28
08:00:00
09:40:00
10:39:59

00:00:00
00:00:00
00:00:01
01:00:00

**Required options**

Set the decrement interval.

Spell Decremented Time

In this example, we paste a list of clock times in the input and subtract 1 minute from each time. The first clock time goes back from today to yesterday and the other times have overflow minutes (minutes counter is more than 60). The program converts all times into valid clock times and spells them in English in the output.

0:0
1:10
2:20
3:30
4:40
5:50
6:60
7:70
8:80
9:90

23 hours and 59 minutes
1 hour and 9 minutes
2 hours and 19 minutes
3 hours and 29 minutes
4 hours and 39 minutes
5 hours and 49 minutes
6 hours and 59 minutes
8 hours and 9 minutes
9 hours and 19 minutes
10 hours and 29 minutes

**Required options**

Set the decrement interval.

Pro tips
Master online time tools

You can pass input to this tool via

__?input__query argument and it will automatically compute output. Here's how to type it in your browser's address bar. Click to try!
https://onlinetimetools.com/decrement-clock-time

__?input__=10%3A20%3A30%0A06%3A00%3A00%0A20%3A50%3A00%0A14%3A40%3A04%0A00%3A30%3A00&interval=1%20hour&format=hh-mm-ss&time-overflow=strict-time
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