diff --git a/src/Illuminate/Support/Number.php b/src/Illuminate/Support/Number.php
index 47d218ffcd47..a9e8097afbb0 100644
--- a/src/Illuminate/Support/Number.php
+++ b/src/Illuminate/Support/Number.php
@@ -124,10 +124,10 @@ public static function currency(int|float $number, string $in = 'USD', ?string $
      */
     public static function fileSize(int|float $bytes, int $precision = 0, ?int $maxPrecision = null)
     {
-        $units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
+        $units = ['B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
 
-        for ($i = 0; ($bytes / 1024) > 0.9 && ($i < count($units) - 1); $i++) {
-            $bytes /= 1024;
+        for ($i = 0; ($bytes / 1000) > 0.9 && ($i < count($units) - 1); $i++) {
+            $bytes /= 1000;
         }
 
         return sprintf('%s %s', static::format($bytes, $precision, $maxPrecision), $units[$i]);
diff --git a/tests/Support/SupportNumberTest.php b/tests/Support/SupportNumberTest.php
index e758ecabdede..30d250dcf852 100644
--- a/tests/Support/SupportNumberTest.php
+++ b/tests/Support/SupportNumberTest.php
@@ -141,18 +141,25 @@ public function testBytesToHuman()
         $this->assertSame('0 B', Number::fileSize(0));
         $this->assertSame('0.00 B', Number::fileSize(0, precision: 2));
         $this->assertSame('1 B', Number::fileSize(1));
-        $this->assertSame('1 KB', Number::fileSize(1024));
-        $this->assertSame('2 KB', Number::fileSize(2048));
-        $this->assertSame('2.00 KB', Number::fileSize(2048, precision: 2));
-        $this->assertSame('1.23 KB', Number::fileSize(1264, precision: 2));
-        $this->assertSame('1.234 KB', Number::fileSize(1264.12345, maxPrecision: 3));
-        $this->assertSame('1.234 KB', Number::fileSize(1264, 3));
+        $this->assertSame('1 kB', Number::fileSize(1000));
+        $this->assertSame('1 kB', Number::fileSize(1024));
+        $this->assertSame('1.02 kB', Number::fileSize(1024, precision: 2));
+        $this->assertSame('2 kB', Number::fileSize(2000));
+        $this->assertSame('2.00 kB', Number::fileSize(2000, precision: 2));
+        $this->assertSame('2 kB', Number::fileSize(2048));
+        $this->assertSame('2.048 kB', Number::fileSize(2048, precision: 3));
+        $this->assertSame('1.26 kB', Number::fileSize(1264, precision: 2));
+        $this->assertSame('1.264 kB', Number::fileSize(1264.12345, maxPrecision: 3));
+        $this->assertSame('1.264 kB', Number::fileSize(1264, 3));
+        $this->assertSame('5 GB', Number::fileSize(1000 * 1000 * 1000 * 5));
+        $this->assertSame('5.37 GB', Number::fileSize(1024 * 1024 * 1024 * 5, precision: 2));
         $this->assertSame('5 GB', Number::fileSize(1024 * 1024 * 1024 * 5));
-        $this->assertSame('10 TB', Number::fileSize((1024 ** 4) * 10));
-        $this->assertSame('10 PB', Number::fileSize((1024 ** 5) * 10));
+        $this->assertSame('10 TB', Number::fileSize((1000 ** 4) * 10));
+        $this->assertSame('11 TB', Number::fileSize((1024 ** 4) * 10));
+        $this->assertSame('11 PB', Number::fileSize((1024 ** 5) * 10));
         $this->assertSame('1 ZB', Number::fileSize(1024 ** 7));
         $this->assertSame('1 YB', Number::fileSize(1024 ** 8));
-        $this->assertSame('1,024 YB', Number::fileSize(1024 ** 9));
+        $this->assertSame('1,238 YB', Number::fileSize(1024 ** 9));
     }
 
     public function testToHuman()