diff --git a/lib/outputcomponents.php b/lib/outputcomponents.php
index c463808e91c..8527eed722f 100644
--- a/lib/outputcomponents.php
+++ b/lib/outputcomponents.php
@@ -5241,7 +5241,7 @@ class progress_bar implements renderable, templatable {
         $this->percent = $percent;
         $this->lastupdate = microtime(true);
 
-        echo $OUTPUT->render_progress_bar_update($this->html_id, sprintf("%.1f", $this->percent), $msg, $estimatemsg);
+        echo $OUTPUT->render_progress_bar_update($this->html_id, $this->percent, $msg, $estimatemsg);
         flush();
     }
 
diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 82ee6ab0062..d5312b07849 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -5140,7 +5140,12 @@ EOD;
      * @return string ascii fragment
      */
     public function render_progress_bar_update(string $id, float $percent, string $msg, string $estimate) : string {
-        return html_writer::script(js_writer::function_call('updateProgressBar', [$id, $percent, $msg, $estimate]));
+        return html_writer::script(js_writer::function_call('updateProgressBar', [
+            $id,
+            round($percent, 1),
+            $msg,
+            $estimate,
+        ]));
     }
 
     /**