1 files changed, 3 insertions, 3 deletions

diff --git a/progress.py b/progress.py
index 54eb8f93..290265c6 100644
--- a/progress.py
+++ b/progress.py
@@ -52,11 +52,11 @@ def duration_str(total):
     uses microsecond resolution.  This makes for noisy output.
     """
     hours, mins, secs = convert_to_hms(total)
-    ret = "%.3fs" % (secs,)
+    ret = f"{secs:.3f}s"
     if mins:
-        ret = "%im%s" % (mins, ret)
+        ret = f"{mins}m{ret}"
     if hours:
-        ret = "%ih%s" % (hours, ret)
+        ret = f"{hours}h{ret}"
     return ret