diff --git a/tutorials/src/bin/basic-tutorial-8.rs b/tutorials/src/bin/basic-tutorial-8.rs
index 2aaa5ba41..e9719c754 100644
--- a/tutorials/src/bin/basic-tutorial-8.rs
+++ b/tutorials/src/bin/basic-tutorial-8.rs
@@ -164,7 +164,7 @@ fn main() {
                         .mul_div_floor(data.num_samples, SAMPLE_RATE as u64)
                         .expect("u64 overflow");
                     let duration = gst::SECOND
-                        .mul_div_floor(CHUNK_SIZE as u64, SAMPLE_RATE as u64)
+                        .mul_div_floor(num_samples as u64, SAMPLE_RATE as u64)
                         .expect("u64 overflow");
 
                     {