diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
index 9bdf7c015..0d6f3fba2 100644
--- a/src/PIL/TiffImagePlugin.py
+++ b/src/PIL/TiffImagePlugin.py
@@ -402,7 +402,7 @@ class IFDRational(Rational):
         f = self._val.limit_denominator(max_denominator)
         return f.numerator, f.denominator
 
-    def __float__(self):
+    def __float__(self) -> float:
         return float(self._val)
 
     def __repr__(self) -> str: