diff --git a/wp-includes/default-constants.php b/wp-includes/default-constants.php
index 358c1018f3..34750057be 100644
--- a/wp-includes/default-constants.php
+++ b/wp-includes/default-constants.php
@@ -41,7 +41,11 @@ function wp_initial_constants() {
 	// set memory limits.
 	if ( function_exists( 'memory_get_usage' ) ) {
 		$current_limit = @ini_get( 'memory_limit' );
-		if ( -1 != $current_limit && ( -1 == WP_MEMORY_LIMIT || ( intval( $current_limit ) < abs( intval( WP_MEMORY_LIMIT ) ) ) ) )
+		$current_limit_int = intval( $current_limit );
+		if ( false !== stripos( $current_limit, 'G' ) )
+			$current_limit_int *= 1024;
+
+		if ( -1 != $current_limit && ( -1 == WP_MEMORY_LIMIT || ( $current_limit_int < abs( intval( WP_MEMORY_LIMIT ) ) ) ) )
 			@ini_set( 'memory_limit', WP_MEMORY_LIMIT );
 	}