diff --git a/src/main.rs b/src/main.rs
index ae69122..3690430 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -160,7 +160,12 @@ struct Progress {
 
 impl Progress {
     fn in_partition(&self, partition: &Partition) -> bool {
-        let current_index = self.count / self.total.div_ceil(partition.count);
+        // div_ceil (stabilized at 1.73) can't be used due to MSRV = 1.70...
+        let mut chunk_count = self.total / partition.count;
+        if self.total % partition.count != 0 {
+            chunk_count += 1;
+        }
+        let current_index = self.count / chunk_count;
         current_index == partition.index
     }
 }