My PHP Performance Benchmarks

PHP version 5.2.17 is running on this server. The benchmarks are done live. Reload the page to get fresh numbers. You are free to use the source for whatever you want. Giving credits to me (Thiemo Mättig) would be nice.

Please note that these are micro benchmarks. Micro benchmarks are stupid. I created this comparison to learn something about PHP and how the PHP compiler works. This can not be used to compare PHP versions or servers.

Check if a String is empty

Method	Undefined	Null	False	Empty string	String "0"	String "1"	Long string	Summary	Index
`if (!$var)`	4 ms	1 ms	1 ms	1 ms	1 ms	>0 ms	>0 ms	7 ms	195
`if (empty($var))`	1 ms	1 ms	1 ms	1 ms	1 ms	>0 ms	>0 ms	5 ms	135
`if ($var == "")`	3 ms	>0 ms	>0 ms	1 ms	>0 ms	>0 ms	42 ms	47 ms	1388
`if ("" == $var)`	2 ms	>0 ms	>0 ms	1 ms	>0 ms	>0 ms	>0 ms	5 ms	144
`if ($var === "")`	2 ms	>0 ms	>0 ms	>0 ms	>0 ms	>0 ms	>0 ms	3 ms	100
`if ("" === $var)`	2 ms	>0 ms	>0 ms	>0 ms	>0 ms	>0 ms	>0 ms	4 ms	112
`if (strcmp($var, "") == 0)`	3 ms	2 ms	2 ms	1 ms	1 ms	1 ms	1 ms	11 ms	331
`if (strcmp("", $var) == 0)`	3 ms	2 ms	2 ms	1 ms	1 ms	1 ms	1 ms	11 ms	329
`if (strlen($var) == 0)`	3 ms	1 ms	1 ms	1 ms	1 ms	1 ms	1 ms	9 ms	268
`if (!strlen($var))`	3 ms	1 ms	1 ms	1 ms	1 ms	1 ms	1 ms	9 ms	262

My conclusion: In most cases, use empty() because it does not trigger a warning when used with undefined variables. Note that empty("0") returns true. Use strlen() if you want to detect "0". Try to avoid == at all because it may cause strange behaviour (e.g. "9a" == 9 returns true). Prefer === over == and !== over != if possible because it does compare the variable types in addition to the contents.

Compare two Strings

Method	Equal	First character not equal	Last character not equal	Summary	Index
`$a == $b`	2 ms	1 ms	2 ms	5 ms	100
`!strcmp($a, $b)`	4 ms	3 ms	4 ms	11 ms	201
`strcmp($a, $b) == 0`	4 ms	3 ms	4 ms	11 ms	214
`strcmp($a, $b) === 0`	4 ms	3 ms	4 ms	11 ms	200
`strcasecmp($a, $b) === 0`	8 ms	3 ms	8 ms	19 ms	353

My conclusion: Use what fits your needs.

Check if a String contains another String

Method	Not found	Found at the start	Found in the middle	Found at the end	Summary	Index
`strstr($haystack, $needle)`	1 ms	1 ms	1 ms	1 ms	4 ms	100
`strpos($haystack, $needle) !== false`	1 ms	1 ms	1 ms	1 ms	4 ms	102
`strstr($haystack, $needle) !== false`	1 ms	1 ms	1 ms	1 ms	4 ms	109
`stristr($haystack, $needle)`	2 ms	2 ms	2 ms	2 ms	8 ms	193
`preg_match("/$needle/", $haystack)`	2 ms	2 ms	2 ms	2 ms	8 ms	190
`preg_match("/$needle/i", $haystack)`	2 ms	2 ms	2 ms	2 ms	8 ms	192
`preg_match("/$needle/S", $haystack)`	2 ms	2 ms	2 ms	2 ms	8 ms	189
`ereg($needle, $haystack)`	2 ms	2 ms	9 ms	17 ms	30 ms	740

My conclusion: It does not matter if you use strstr() or strpos(). Use the preg…() functions only if you need the power of regular expressions. Never use the ereg…() functions.

Check if a String starts with another String

Method	Not found	Found at the start	Found in the middle	Found at the end	Summary	Index
`strncmp($haystack, $needle, strlen($needle)) === 0`	1 ms	1 ms	1 ms	1 ms	6 ms	157
`strncmp($haystack, "Test", 4) === 0`	1 ms	1 ms	1 ms	1 ms	4 ms	101
`strncasecmp($haystack, $needle, strlen($needle)) === 0`	1 ms	2 ms	2 ms	2 ms	6 ms	164
`strpos($haystack, $needle) === 0`	1 ms	1 ms	1 ms	1 ms	4 ms	100
`substr($haystack, 0, strlen($needle)) === $needle`	2 ms	2 ms	2 ms	2 ms	6 ms	167
`strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0`	2 ms	2 ms	2 ms	2 ms	9 ms	241
`preg_match("/^" . preg_quote($needle, "/") . "/", $haystack)`	3 ms	3 ms	3 ms	3 ms	12 ms	319

My conclusion: strpos() is very fast and can be used in almost all cases. strncmp() is good if you are looking for a constant length needle.

Check if a String ends with another String

Method	Not found	Found at the start	Found in the middle	Found at the end	Summary	Index
`substr($haystack, strlen($haystack) - strlen($needle)) === $needle`	2 ms	2 ms	2 ms	2 ms	8 ms	100
`substr($haystack, -strlen($needle)) === $needle`	2 ms	2 ms	3 ms	3 ms	9 ms	116
`strcmp(substr($haystack, -strlen($needle)), $needle) === 0`	3 ms	4 ms	3 ms	4 ms	14 ms	184
`preg_match("/" . preg_quote($needle, "/") . "$/", $haystack)`	6 ms	5 ms	3 ms	4 ms	18 ms	235

My conclusion: Using substr() with a negative position is a good trick.

Replace a String inside another String

Method	Not found	Found at the start	Found in the middle	Found at the end	Summary	Index
`str_replace($search, $replace, $subject)`	3 ms	2 ms	2 ms	3 ms	10 ms	100
`preg_replace("/$search/", $replace, $subject)`	4 ms	5 ms	3 ms	3 ms	15 ms	155
`preg_replace("/$search/S", $replace, $subject)`	3 ms	3 ms	3 ms	3 ms	13 ms	127
`ereg_replace($search, $replace, $subject)`	3 ms	6 ms	12 ms	20 ms	41 ms	417
`strtr($subject, $array)`	18 ms	17 ms	12 ms	12 ms	59 ms	601

My conclusion: Never use the ereg…() functions.

Trim Characters from the Beginning and End of a String

Method	Not found	Found at start	Found at end	Found at both sides	Summary	Index
`trim($string, ",")`	>0 ms	>0 ms	>0 ms	>0 ms	1 ms	100
`preg_replace('/^,\|,$/', "", $string)`	7 ms	7 ms	7 ms	7 ms	29 ms	3899
`preg_replace('/^,\|,$/m', "", $string)`	12 ms	12 ms	12 ms	12 ms	47 ms	6425
`preg_replace('/^,+\|,+$/', "", $string)`	>0 ms	>0 ms	>0 ms	>0 ms	2 ms	245
`preg_replace('/^,+\|,+$/m', "", $string)`	>0 ms	>0 ms	>0 ms	>0 ms	2 ms	237
`preg_replace('/^,+/', "", preg_replace('/,+$/', "", …))`	1 ms	1 ms	1 ms	1 ms	3 ms	409

My conclusion: Always benchmark your regular expressions! In this case, with .* you also replace nothing with nothing which takes time because there is a lot of “nothing” in every string.

Split a String into an Array

Method	Empty string	Single occurrence	Multiple occurrences	Summary	Index
`explode(",", $string)`	1 ms	1 ms	7 ms	10 ms	100
`split(",", $string)`	1 ms	2 ms	40 ms	43 ms	444
`preg_split("/,/", $string)`	2 ms	2 ms	11 ms	15 ms	152
`preg_match_all('/[^,]+/', $string, $matches)`	2 ms	3 ms	18 ms	23 ms	239

My conclusion: Don't use split(). It's deprecated in PHP 5.3 and will be removed in PHP 6.

Loop a numerical indexed Array of Strings

Method	Summary	Index
`for ($i = 0; $i < count($array); $i++)`	42 ms	5846
`for ($i = 0, $count = count($array); $i < $count; $i++)`	1 ms	141
`for ($i = count($array) - 1; $i >= 0; $i--)`	1 ms	136
`for ($i = count($array) - 1; $i >= 0; --$i)`	1 ms	131
`$i = count($array); while ($i--)`	1 ms	100

My conclusion: count() is horribly slow. Always precalculate it, if possible.

Get Elements from an Array

Method	Summary	Index
`$array[0]`	33 ms	100
`$array['key']`	33 ms	100

My conclusion: I like associative arrays.

Implode an Array

Method	Summary	Index
`implode(" ", $array)`	5 ms	100
`"$array[0] $array[1] $array[2]"`	5 ms	111
`$array[0] . " " . $array[1] . " " . $array[2]`	5 ms	103
`sprintf("%s %s %s", $array[0], $array[1], $array[2])`	10 ms	216
`vsprintf("%s %s %s", $array)`	12 ms	254

My conclusion: String concatenation is a cheap operation in PHP. Don't waste your time benchmarking this.

The single vs. double Quotes Myth

Method	Summary	Index
`'contains no dollar signs'`	1 ms	109
`"contains no dollar signs"`	1 ms	109
`'$variables $are $not $replaced'`	1 ms	108
`"\$variables \$are \$not \$replaced"`	1 ms	100
`"$variables $are $replaced"`	7 ms	1263
`$variables . ' ' . $are . ' ' . $replaced`	8 ms	1407
`$variables . " " . $are . " " . $replaced`	8 ms	1403

My conclusion: It does not matter if you use single or double quotes at all. The inclusion of variables has a measurable effect, but that's independent from the quotes.