(PHP 4, PHP 5, PHP 7, PHP 8)
microtime — Return current Unix timestamp with microseconds
microtime() returns the current Unix timestamp with microseconds. This function is only available on operating systems that support the gettimeofday() system call.
For performance measurements, using hrtime() is recommended.
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.
Example #1 Timing script execution
<?php
$time_start = microtime(true);
// Sleep for a while
usleep(100);
$time_end = microtime(true);
$time = $time_end - $time_start;
echo "Did nothing in $time seconds\n";
?>Example #2 microtime() and REQUEST_TIME_FLOAT
<?php
// 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 "Did nothing in $time seconds\n";
?>