How to get the current unix timestamp in php using microtime?

(PHP 4, PHP 5, PHP 7, PHP 8)

microtime — Return current Unix timestamp with microseconds

Description

microtime(bool $as_float = false): string|float

For performance measurements, using hrtime() is recommended.

Parameters

If used and set to true, microtime() will return a float instead of a string, as described in the return values section below.

Return Values

By default, microtime() returns a string in the form "msec sec", where sec is the number of seconds since the Unix epoch (0:00:00 January 1,1970 GMT), and msec measures microseconds that have elapsed since sec and is also expressed in seconds as a decimal fraction.

If as_float is set to true, then microtime() returns a float, which represents the current time in seconds since the Unix epoch accurate to the nearest microsecond.

Examples

Example #1 Timing script execution

$time_start = microtime(true);// Sleep for a while
usleep(100);$time_end = microtime(true);
$time = $time_end - $time_start;

echo

Example #2 microtime() and REQUEST_TIME_FLOAT

// Randomize sleeping time
usleep(mt_rand(100, 10000));// REQUEST_TIME_FLOAT is available in the $_SERVER superglobal array.
// It contains the timestamp of the start of the request with microsecond precision.
$time = microtime(true) - $_SERVER["REQUEST_TIME_FLOAT"];

echo

See Also

• time() - Return current Unix timestamp
• hrtime() - Get the system's high resolution time

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));
}

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