diff --git a/lib/private/legacy/OC_Helper.php b/lib/private/legacy/OC_Helper.php
index 33cc966da2a6e..a535793b3433d 100644
--- a/lib/private/legacy/OC_Helper.php
+++ b/lib/private/legacy/OC_Helper.php
@@ -40,7 +40,7 @@ class OC_Helper {
 	 * @param int|float $bytes file size in bytes
 	 * @return string a human readable file size
 	 *
-	 * Makes 2048 to 2 kB.
+	 * Makes 2048 to 2 KiB.
 	 */
 	public static function humanFileSize(int|float $bytes): string {
 		if ($bytes < 0) {
@@ -51,23 +51,23 @@ public static function humanFileSize(int|float $bytes): string {
 		}
 		$bytes = round($bytes / 1024, 0);
 		if ($bytes < 1024) {
-			return "$bytes KB";
+			return "$bytes KiB";
 		}
 		$bytes = round($bytes / 1024, 1);
 		if ($bytes < 1024) {
-			return "$bytes MB";
+			return "$bytes MiB";
 		}
 		$bytes = round($bytes / 1024, 1);
 		if ($bytes < 1024) {
-			return "$bytes GB";
+			return "$bytes GiB";
 		}
 		$bytes = round($bytes / 1024, 1);
 		if ($bytes < 1024) {
-			return "$bytes TB";
+			return "$bytes TiB";
 		}
 
 		$bytes = round($bytes / 1024, 1);
-		return "$bytes PB";
+		return "$bytes PiB";
 	}
 
 	/**
diff --git a/tests/lib/LegacyHelperTest.php b/tests/lib/LegacyHelperTest.php
index 85960ef6f08c5..b467bb3c69e48 100644
--- a/tests/lib/LegacyHelperTest.php
+++ b/tests/lib/LegacyHelperTest.php
@@ -34,12 +34,12 @@ public function testHumanFileSize($expected, $input) {
 	public function humanFileSizeProvider() {
 		return [
 			['0 B', 0],
-			['1 KB', 1024],
-			['9.5 MB', 10000000],
-			['1.3 GB', 1395864371],
-			['465.7 GB', 500000000000],
-			['454.7 TB', 500000000000000],
-			['444.1 PB', 500000000000000000],
+			['1 KiB', 1024],
+			['9.5 MiB', 10000000],
+			['1.3 GiB', 1395864371],
+			['465.7 GiB', 500000000000],
+			['454.7 TiB', 500000000000000],
+			['444.1 PiB', 500000000000000000],
 		];
 	}