How to get current time in milliseconds in PHP?

time() is in seconds - is there one in milliseconds?

Solution 1:

The short answer is:

$milliseconds = round(microtime(true) * 1000);

Solution 2:

Use microtime. This function returns a string separated by a space. The first part is the fractional part of seconds, the second part is the integral part. Pass in true to get as a number:

var_dump(microtime());       // string(21) "0.89115400 1283846202"
var_dump(microtime(true));   // float(1283846202.89)

Beware of precision loss if you use microtime(true).

There is also gettimeofday that returns the microseconds part as an integer.

var_dump(gettimeofday());
/*
array(4) {
  ["sec"]=>
  int(1283846202)
  ["usec"]=>
  int(891199)
  ["minuteswest"]=>
  int(-60)
  ["dsttime"]=>
  int(1)
}
*/

Solution 3:

Short answer:

64 bits platforms only!

function milliseconds() {
    $mt = explode(' ', microtime());
    return ((int)$mt[1]) * 1000 + ((int)round($mt[0] * 1000));
}

[ If you are running 64 bits PHP then the constant PHP_INT_SIZE equals to 8 ]

Long answer:

If you want an equilvalent function of time() in milliseconds first you have to consider that as time() returns the number of seconds elapsed since the "epoch time" (01/01/1970), the number of milliseconds since the "epoch time" is a big number and doesn't fit into a 32 bits integer.

The size of an integer in PHP can be 32 or 64 bits depending on platform.

From http://php.net/manual/en/language.types.integer.php

The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed). 64-bit platforms usually have a maximum value of about 9E18, except for Windows, which is always 32 bit. PHP does not support unsigned integers. Integer size can be determined using the constant PHP_INT_SIZE, and maximum value using the constant PHP_INT_MAX since PHP 4.4.0 and PHP 5.0.5.

If you have 64 bits integers then you may use the following function:

function milliseconds() {
    $mt = explode(' ', microtime());
    return ((int)$mt[1]) * 1000 + ((int)round($mt[0] * 1000));
}

microtime() returns the number of seconds since the "epoch time" with precision up to microseconds with two numbers separated by space, like...

0.90441300 1409263371

The second number is the seconds (integer) while the first one is the decimal part.

The above function milliseconds() takes the integer part multiplied by 1000

1409263371000

then adds the decimal part multiplied by 1000 and rounded to 0 decimals

1409263371904

Note that both $mt[1] and the result of round are casted to int. This is necessary because they are floats and the operation on them without casting would result in the function returning a float.

Finally, that function is slightly more precise than

round(microtime(true)*1000);

that with a ratio of 1:10 (approx.) returns 1 more millisecond than the correct result. This is due to the limited precision of the float type (microtime(true) returns a float). Anyway if you still prefer the shorter round(microtime(true)*1000); I would suggest casting to int the result.

Even if it's beyond the scope of the question it's worth mentioning that if your platform supports 64 bits integers then you can also get the current time in microseconds without incurring in overflow.

If fact 2^63 - 1 (biggest signed integer) divided by 10^6 * 3600 * 24 * 365 (approximately the microseconds in one year) gives 292471.

That's the same value you get with

echo (int)( PHP_INT_MAX / ( 1000000 * 3600 * 24 * 365 ) );

In other words, a signed 64 bits integer have room to store a timespan of over 200,000 years measured in microseconds.

You may have then

function microseconds() {
    $mt = explode(' ', microtime());
    return ((int)$mt[1]) * 1000000 + ((int)round($mt[0] * 1000000));
}

Solution 4:

As other have stated, you can use microtime() to get millisecond precision on timestamps.

From your comments, you seem to want it as a high-precision UNIX Timestamp. Something like DateTime.Now.Ticks in the .NET world.

You may use the following function to do so:

function millitime() {
  $microtime = microtime();
  $comps = explode(' ', $microtime);

  // Note: Using a string here to prevent loss of precision
  // in case of "overflow" (PHP converts it to a double)
  return sprintf('%d%03d', $comps[1], $comps[0] * 1000);
}