diff --git a/src/NanoVNASaver/Charts/TDR.py b/src/NanoVNASaver/Charts/TDR.py
index 9a91e05..5e75ed4 100644
--- a/src/NanoVNASaver/Charts/TDR.py
+++ b/src/NanoVNASaver/Charts/TDR.py
@@ -388,11 +388,11 @@ class TDRChart(Chart):
         qp.drawText(
             self.leftMargin - 10,
             self.topMargin + height + 15,
-            f"""{
+            f"""{{
                 round(
                     self.tdrWindow.distance_axis[min_index] / 2, self.decimals
                 )!s
-            }m""",
+            }}m""",
         )
 
     def _draw_y_ticks(