diff --git a/src/calculator.py b/src/calculator.py
index e4e6afd..6e01139 100644
--- a/src/calculator.py
+++ b/src/calculator.py
@@ -20,3 +20,9 @@ def clamp(value: int, low: int, high: int) -> int:
 
 def clamp_to_byte(value: int) -> int:
     return max(0, min(255, value))
+
+
+def average(values: list[int | float]) -> float:
+    if not values:
+        raise ValueError
+    return sum(values) / len(values)