diff --git a/cf/data/data.py b/cf/data/data.py
index d84cfc395c..d41c451f3c 100644
--- a/cf/data/data.py
+++ b/cf/data/data.py
@@ -8812,9 +8812,8 @@ def equals(
         other_Units = other.Units
         if self_Units != other_Units:
             logger.info(
-                "{}: Different Units ({!r}, {!r})".format(
-                    self.__class__.__name__, self.Units, other.Units
-                )
+                f"{self.__class__.__name__}: Different Units "
+                f"({self.Units!r}, {other.Units!r})"
             )
             return False
 
@@ -8828,8 +8827,8 @@ def equals(
             self_dx, other_dx, rtol=float(rtol), atol=float(atol)
         ):
             logger.info(
-                "{0}: Different array values (atol={1}, "
-                "rtol={2})".format(self.__class__.__name__, atol, rtol)
+                f"{self.__class__.__name__}: Different array values "
+                f"(atol={atol}, rtol={rtol})"
             )
 
             return False