diff --git a/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/duration.md b/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/duration.md
index b61f50917..ed7c9c13b 100644
--- a/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/duration.md
+++ b/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/duration.md
@@ -27,7 +27,8 @@ The value to convert.
 _**Data type:** Integer | String | Uinteger_
 
 {{% note %}}
-`duration()` assumes numeric input values are **nanoseconds**.
+`duration()` assumes **numeric** input values are **nanoseconds**.
+**String** input values must use [duration literal representation](#/v2.0/reference/flux/language/lexical-elements/#duration-literals).
 {{% /note %}}
 
 ## Examples
diff --git a/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/toduration.md b/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/toduration.md
index 21d2ce5cf..d66b51b26 100644
--- a/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/toduration.md
+++ b/content/v2.0/reference/flux/stdlib/built-in/transformations/type-conversions/toduration.md
@@ -26,7 +26,8 @@ toDuration()
 _**Supported data types:** Integer | String | Uinteger_
 
 {{% note %}}
-`toDuration()` assumes numeric input values are **nanoseconds**.
+`duration()` assumes **numeric** input values are **nanoseconds**.
+**String** input values must use [duration literal representation](#/v2.0/reference/flux/language/lexical-elements/#duration-literals).
 {{% /note %}}
 
 {{% note %}}