diff --git a/src/Utils.php b/src/Utils.php
index f581ca1..0fd54ca 100644
--- a/src/Utils.php
+++ b/src/Utils.php
@@ -397,4 +397,30 @@ class Utils
         }
         return $json;
     }
+
+    /**
+     * toBn
+     * Change number or number string to bignumber.
+     * 
+     * @param BigNumber|string|int $number
+     * @return \phpseclib\Math\BigInteger
+     */
+    public static function toBn($number)
+    {
+        if (is_int($number)) {
+            $bn = new BigNumber($number);
+        } elseif (is_string($number)) {
+            $number = mb_strtolower($number);
+
+            if (self::isZeroPrefixed($number)) {
+                $number = self::stripZero($number);
+                $bn = new BigNumber($number, 16);
+            } else {
+                $bn = new BigNumber($number);
+            }
+        } elseif (!$number instanceof BigNumber){
+            throw new InvalidArgumentException('toBn number must be BigNumber, string or int.');
+        }
+        return $bn;
+    }
 }
\ No newline at end of file
diff --git a/test/unit/UtilsTest.php b/test/unit/UtilsTest.php
index 84b4522..de95360 100644
--- a/test/unit/UtilsTest.php
+++ b/test/unit/UtilsTest.php
@@ -4,6 +4,7 @@ namespace Test\Unit;
 
 use InvalidArgumentException;
 use Test\TestCase;
+use phpseclib\Math\BigInteger;
 use Web3\Utils;
 
 class UtilsTest extends TestCase
@@ -386,4 +387,24 @@ class UtilsTest extends TestCase
 
         $this->assertFalse($isHex);
     }
+
+    /**
+     * testToBn
+     * 
+     * @return void
+     */
+    public function testToBn()
+    {
+        $bn = Utils::toBn(11);
+
+        $this->assertEquals($bn->toString(), '11');
+
+        $bn = Utils::toBn('0x12');
+
+        $this->assertEquals($bn->toString(), '18');
+
+        $bn = Utils::toBn(0x12);
+
+        $this->assertEquals($bn->toString(), '18');
+    }
 }
\ No newline at end of file