diff --git a/units/src/weight.rs b/units/src/weight.rs
index c7fb19913..ecd50b804 100644
--- a/units/src/weight.rs
+++ b/units/src/weight.rs
@@ -48,7 +48,13 @@ impl Weight {
     pub const fn from_wu(wu: u64) -> Self { Weight(wu) }
 
     /// Constructs a new [`Weight`] from kilo weight units returning [`None`] if an overflow occurred.
-    pub fn from_kwu(wu: u64) -> Option<Self> { wu.checked_mul(1000).map(Weight) }
+    pub const fn from_kwu(wu: u64) -> Option<Self> {
+        // No `map()` in const context.
+        match wu.checked_mul(1000) {
+            Some(wu) => Some(Weight::from_wu(wu)),
+            None => None,
+        }
+    }
 
     /// Constructs a new [`Weight`] from virtual bytes, returning [`None`] if an overflow occurred.
     pub const fn from_vb(vb: u64) -> Option<Self> {