diff --git a/ext/standard/math.c b/ext/standard/math.c
index 05f2252e304e..fc2d926e1ff6 100644
--- a/ext/standard/math.c
+++ b/ext/standard/math.c
@@ -184,7 +184,7 @@ PHPAPI double _php_math_round(double value, int places, int mode) {
 
 	/* If the decimal precision guaranteed by FP arithmetic is higher than
 	   the requested places BUT is small enough to make sure a non-zero value
-	   is returned, pre-round the result to the precision */
+	   is returned, adjust result digits to the precision */
 	if (precision_places > places && precision_places - 15 < places) {
 		int64_t use_precision = precision_places < INT_MIN+1 ? INT_MIN+1 : precision_places;
 
@@ -194,9 +194,9 @@ PHPAPI double _php_math_round(double value, int places, int mode) {
 		} else {
 			tmp_value = value / f2;
 		}
-		/* preround the result (tmp_value will always be something * 1e14,
+		/* adjust result digits (tmp_value will always be something * 1e14,
 		   thus never larger than 1e15 here) */
-		tmp_value = php_round_helper(tmp_value, mode);
+		tmp_value = (tmp_value >= 0.0) ? floor(tmp_value) : ceil(tmp_value);
 
 		use_precision = places - precision_places;
 		use_precision = use_precision < INT_MIN+1 ? INT_MIN+1 : use_precision;
diff --git a/ext/standard/tests/math/bug24142.phpt b/ext/standard/tests/math/bug24142.phpt
index 947deaebd669..739ac25421dc 100644
--- a/ext/standard/tests/math/bug24142.phpt
+++ b/ext/standard/tests/math/bug24142.phpt
@@ -2,19 +2,65 @@
 Bug #24142 (round() problems)
 --FILE--
 <?php
-$v = 0.005;
-for ($i = 1; $i < 10; $i++) {
-    echo "round({$v}, 2) -> ".round($v, 2)."\n";
-    $v += 0.01;
-}
+echo "round(0.005, 2)\n";
+var_dump(round(0.005, 2));
+echo "\n";
+
+echo "round(0.015, 2)\n";
+var_dump(round(0.015, 2));
+echo "\n";
+
+echo "round(0.025, 2)\n";
+var_dump(round(0.025, 2));
+echo "\n";
+
+echo "round(0.035, 2)\n";
+var_dump(round(0.035, 2));
+echo "\n";
+
+echo "round(0.045, 2)\n";
+var_dump(round(0.045, 2));
+echo "\n";
+
+echo "round(0.055, 2)\n";
+var_dump(round(0.055, 2));
+echo "\n";
+
+echo "round(0.065, 2)\n";
+var_dump(round(0.065, 2));
+echo "\n";
+
+echo "round(0.075, 2)\n";
+var_dump(round(0.075, 2));
+echo "\n";
+
+echo "round(0.085, 2)\n";
+var_dump(round(0.085, 2));
 ?>
 --EXPECT--
-round(0.005, 2) -> 0.01
-round(0.015, 2) -> 0.02
-round(0.025, 2) -> 0.03
-round(0.035, 2) -> 0.04
-round(0.045, 2) -> 0.05
-round(0.055, 2) -> 0.06
-round(0.065, 2) -> 0.07
-round(0.075, 2) -> 0.08
-round(0.085, 2) -> 0.09
+round(0.005, 2)
+float(0.01)
+
+round(0.015, 2)
+float(0.02)
+
+round(0.025, 2)
+float(0.03)
+
+round(0.035, 2)
+float(0.04)
+
+round(0.045, 2)
+float(0.05)
+
+round(0.055, 2)
+float(0.06)
+
+round(0.065, 2)
+float(0.07)
+
+round(0.075, 2)
+float(0.08)
+
+round(0.085, 2)
+float(0.09)
diff --git a/ext/standard/tests/math/round_gh12143_adjustment_result_digit.phpt b/ext/standard/tests/math/round_gh12143_adjustment_result_digit.phpt
new file mode 100644
index 000000000000..4917ee88d5e9
--- /dev/null
+++ b/ext/standard/tests/math/round_gh12143_adjustment_result_digit.phpt
@@ -0,0 +1,55 @@
+--TEST--
+Fix GH-12143: Improved handling of adjusting result digits
+--FILE--
+<?php
+echo "HALF_UP\n";
+var_dump(round(1.700000000000145, 13, PHP_ROUND_HALF_UP));
+var_dump(round(-1.700000000000145, 13, PHP_ROUND_HALF_UP));
+var_dump(round(123456789012344.5, -1, PHP_ROUND_HALF_UP));
+var_dump(round(-123456789012344.5, -1, PHP_ROUND_HALF_UP));
+echo "\n";
+
+echo "HALF_DOWN\n";
+var_dump(round(1.700000000000156, 13, PHP_ROUND_HALF_DOWN));
+var_dump(round(-1.700000000000156, 13, PHP_ROUND_HALF_DOWN));
+var_dump(round(123456789012345.6, -1, PHP_ROUND_HALF_DOWN));
+var_dump(round(-123456789012345.7, -1, PHP_ROUND_HALF_DOWN));
+echo "\n";
+
+echo "HALF_EVEN\n";
+var_dump(round(1.700000000000255, 13, PHP_ROUND_HALF_EVEN));
+var_dump(round(-1.700000000000255, 13, PHP_ROUND_HALF_EVEN));
+var_dump(round(12345678901234.55, 0, PHP_ROUND_HALF_EVEN));
+var_dump(round(-12345678901234.55, 0, PHP_ROUND_HALF_EVEN));
+echo "\n";
+
+echo "HALF_ODD\n";
+var_dump(round(1.700000000000756, 13, PHP_ROUND_HALF_ODD));
+var_dump(round(-1.700000000000757, 13, PHP_ROUND_HALF_ODD));
+var_dump(round(12345678901233.56, 0, PHP_ROUND_HALF_ODD));
+var_dump(round(-12345678901233.56, 0, PHP_ROUND_HALF_ODD));
+?>
+--EXPECT--
+HALF_UP
+float(1.7000000000001)
+float(-1.7000000000001)
+float(123456789012340)
+float(-123456789012340)
+
+HALF_DOWN
+float(1.7000000000001)
+float(-1.7000000000001)
+float(123456789012340)
+float(-123456789012340)
+
+HALF_EVEN
+float(1.7000000000002)
+float(-1.7000000000002)
+float(12345678901234)
+float(-12345678901234)
+
+HALF_ODD
+float(1.7000000000007)
+float(-1.7000000000007)
+float(12345678901233)
+float(-12345678901233)