# Converting To And From Decimal Time In PHP

To convert a time value into a decimal value representing the number of minutes can be useful for certain calculations. The following function takes a time as a string of hh:mm:ss and returns a decimal value in minutes.

``````/**
* Convert time into decimal time.
*
* @param string \$time The time to convert
*
* @return integer The time as a decimal value.
*/
function time_to_decimal(\$time) {
\$timeArr = explode(':', \$time);
\$decTime = (\$timeArr*60) + (\$timeArr) + (\$timeArr/60);

return \$decTime;
}``````

If we take the time of 11:11:11 this gets split into 3 parts by the explode() function into hours, minutes and seconds, which then gets treated in the following way:

``````Minutes = (Hours x 60) + (Minutes) + (Seconds / 60)
Minutes = (11 x 60) + (11) + (11 / 60)
Minutes = (660) + (11) + (0.18333333)
Minutes = 671.18333333``````

The function can be used as follows:

``echo time_to_decimal("11:11:11"); // prints 671.18333333``

The reverse of this function takes the decimal value and returns a string in the format hh:mm:ss.

``````/**
* Convert decimal time into time in the format hh:mm:ss
*
* @param integer The time as a decimal value.
*
* @return string \$time The converted time value.
*/
function decimal_to_time(\$decimal) {
\$hours = floor(\$decimal / 60);
\$minutes = floor(\$decimal % 60);
\$seconds = \$decimal - (int)\$decimal;
\$seconds = round(\$seconds * 60);

}``````

This function can be used as follows:

``echo decimal_to_time(671.18333333); // prints 11:11:11``

Note that these functions deal with amounts of time, not the time of day. Converting between time and decimal time of day requires a different set of calculations.

UPDATE: Thanks to an anonymous poster for pointing out some errors, these have now been corrected.

Hi Philip,

Your code indeed works in the manner you have described, however there are a couple of finer details that caused issues for me when using the code.

In the time_to_decimal function, line 12 should read as follows:

``\$decTime = (\$timeArr*60) + (\$timeArr) + (\$timeArr/60);``

As it is written in your post, the seconds are actually representing fractions of an hour (1/3600th) as opposed to fractions of a minute (1/60th).

We have the same issue in the decimal_to_time function as well as an issue in regards to the round() function.  I've corrected the decimal_to_time function as follows:

``````function decimal_to_time(\$decimal) {
\$hours = floor((int)\$decimal / 60);
\$minutes = floor((int)\$decimal % 60);
\$seconds = \$decimal - (int)\$decimal;
\$seconds = round(\$seconds * 60);

}``````

round() in lines 2 and 3 have been replaced by floor().  This is due to the behavior of round() returning 1 when given .5.  An example is as follows:

Say we are converting 1:30:30 into a decimal representing minutes.  Using the two functions posted we would have

``````echo time_to_decimal('1:30:30'); // prints 90.008333333333, seconds are still converted incorrectly

// this should display the input from the first function
echo decimal_to_time(90.008333333333); // prints 02:02:30, not correct``````

In the example, line 2 of the original code calculates to - round( 90 / 60 ) = round(1.5) = 2.  Since we only want the numer of whole hours in the \$decimal variable, we should use floor() instead.  floor() will always round to the lowest whole number ( 1 in this case )

I hope this helps someone out there :)

Thank you for all the hard work you put into that comment! I really appreciate it when a user posts such detailed comments on this blog :)

I have tested your examples and updated my code accordingly.

Name
Philip Norton

hi tae, thanks..

i propose to change little to allow this kind of input "01:05" =1h05 or "01:05:00" or "01"=1hour

``````function time_to_decimal(\$time) {
\$timeArr = explode(':', \$time);
if (count(\$timeArr) == 3) {
\$decTime = (\$timeArr*60) + (\$timeArr) + (\$timeArr/60);
} else if (count(\$timeArr) == 2) {
\$decTime = (\$timeArr) + (\$timeArr/60);
} else if (count(\$timeArr) == 2) {
\$decTime = \$time;
}
return \$decTime;
}``````

This function kept returning :60 in the seconds place! I added :

``````if (\$seconds == 60) {
\$minutes++; \$seconds=0;
}
``````

to the end of the function.

My 2 cents comment if used your function and added a format control to avoid strange behavior and surprise

``````function Time_To_Decimal(\$time) {
\$decTime = 0;
if (preg_match("/^([0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9])\$/", \$time, \$matches)) {
\$decTime = (\$matches*60) + (\$matches) + (\$matches/60);
}
return \$decTime;
}
``````

Thanks a lot for posting

Sorry posted too quickly (fixed preg_match return array)

``````function Time_To_Decimal(\$time) {
\$decTime = 0;
if (preg_match("/^([0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9])\$/", \$time, \$matches)) {
\$decTime = (\$matches*60) + (\$matches) + (\$matches/60);
}
return \$decTime;
}``````
gmmktime() -> time 2 decimal

Error here

``floor(\$decimal % 60);``

and not

``floor(\$decimal % / 60);``