diff --git a/core/config/schema/core.data_types.schema.yml b/core/config/schema/core.data_types.schema.yml
index 4694cf69713..ca95ffc2e85 100644
--- a/core/config/schema/core.data_types.schema.yml
+++ b/core/config/schema/core.data_types.schema.yml
@@ -160,6 +160,14 @@ langcode:
     Choice:
       callback: 'Drupal\Core\TypedData\Plugin\DataType\LanguageReference::getAllValidLangcodes'
 
+# A number of bytes; either a plain number or with a size indication such as "MB".
+# @see \Drupal\Component\Utility\Bytes
+bytes:
+  type: string
+  label: 'Bytes'
+  constraints:
+    Callback: ['\Drupal\Component\Utility\Bytes', 'validateConstraint']
+
 # Complex extended data types:
 
 # Root of a configuration object.
diff --git a/core/lib/Drupal/Component/Utility/Bytes.php b/core/lib/Drupal/Component/Utility/Bytes.php
index 8b8de6d4071..429b6b428b8 100644
--- a/core/lib/Drupal/Component/Utility/Bytes.php
+++ b/core/lib/Drupal/Component/Utility/Bytes.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Component\Utility;
 
+use Symfony\Component\Validator\Context\ExecutionContextInterface;
+
 /**
  * Provides helper methods for byte conversions.
  */
@@ -109,4 +111,30 @@ class Bytes {
     return in_array(strtolower($string), self::ALLOWED_SUFFIXES);
   }
 
+  /**
+   * Validates a string is a representation of a number of bytes.
+   *
+   * To be used with the `Callback` constraint.
+   *
+   * @param string|int|float|null $value
+   *   The string, integer or float to validate.
+   * @param \Symfony\Component\Validator\Context\ExecutionContextInterface $context
+   *   The validation execution context.
+   *
+   * @see \Symfony\Component\Validator\Constraints\CallbackValidator
+   * @see core/config/schema/core.data_types.schema.yml
+   */
+  public static function validateConstraint(string|int|float|null $value, ExecutionContextInterface $context): void {
+    // Ignore NULL values (i.e. support `nullable: true`).
+    if ($value === NULL) {
+      return;
+    }
+
+    if (!self::validate((string) $value)) {
+      $context->addViolation('This value must be a number of bytes, optionally with a unit such as "MB" or "megabytes". %value does not represent a number of bytes.', [
+        '%value' => $value,
+      ]);
+    }
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/Component/Utility/BytesTest.php b/core/tests/Drupal/Tests/Component/Utility/BytesTest.php
index 3ec6e091316..d8c9c5ce222 100644
--- a/core/tests/Drupal/Tests/Component/Utility/BytesTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/BytesTest.php
@@ -6,7 +6,10 @@ namespace Drupal\Tests\Component\Utility;
 
 use Drupal\Component\Utility\Bytes;
 use PHPUnit\Framework\TestCase;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
 use Symfony\Bridge\PhpUnit\ExpectDeprecationTrait;
+use Symfony\Component\Validator\Context\ExecutionContextInterface;
 
 /**
  * Tests bytes size parsing helper methods.
@@ -18,6 +21,7 @@ use Symfony\Bridge\PhpUnit\ExpectDeprecationTrait;
 class BytesTest extends TestCase {
 
   use ExpectDeprecationTrait;
+  use ProphecyTrait;
 
   /**
    * Tests \Drupal\Component\Utility\Bytes::toNumber().
@@ -88,6 +92,17 @@ class BytesTest extends TestCase {
    */
   public function testValidate($string, bool $expected_result): void {
     $this->assertSame($expected_result, Bytes::validate($string));
+
+    $execution_context = $this->prophesize(ExecutionContextInterface::class);
+    if ($expected_result) {
+      $execution_context->addViolation(Argument::cetera())
+        ->shouldNotBeCalled();
+    }
+    else {
+      $execution_context->addViolation(Argument::cetera())
+        ->shouldBeCalledTimes(1);
+    }
+    Bytes::validateConstraint($string, $execution_context->reveal());
   }
 
   /**