diff --git a/src/api/res.py b/src/api/res.py
index 9cf95960..e2021db5 100644
--- a/src/api/res.py
+++ b/src/api/res.py
@@ -90,6 +90,16 @@ def res(
             "Please choose one or the other."
         )
 
+    if sigfigs is not None and isinstance(value, str):
+        raise ValueError(
+            "You can't set sigfigs and supply an exact value. Please do one or the other."
+        )
+
+    if decimal_places is not None and isinstance(value, str):
+        raise ValueError(
+            "You can't set decimal places and supply an exact value. Please do one or the other."
+        )
+
     # Parse user input
     name_res = parsers.parse_name(name)
     value_res = parsers.parse_value(value)
diff --git a/src/application/rounder.py b/src/application/rounder.py
index 7c1847ae..a8cc168f 100644
--- a/src/application/rounder.py
+++ b/src/application/rounder.py
@@ -58,8 +58,6 @@ def round_result(cls, result: Result, config: RoundingConfig) -> None:
 
         8. Is fallback for decimal places given (not -1) (see config)?
            Round value according to number of decimal places.
-
-        TODO: Warning message if user specifies exact value and sigfigs etc.
         """
         cls._round_result(result, config)