diff --git a/src/libcore/num/int_macros.rs b/src/libcore/num/int_macros.rs
index fe0d6d13c4c0..3113521e0aff 100644
--- a/src/libcore/num/int_macros.rs
+++ b/src/libcore/num/int_macros.rs
@@ -15,11 +15,11 @@ macro_rules! int_module { ($T:ty, $bits:expr) => (
 // FIXME(#11621): Should be deprecated once CTFE is implemented in favour of
 // calling the `mem::size_of` function.
 #[unstable(feature = "core")]
-pub const BITS : u32 = $bits;
+pub const BITS : usize = $bits;
 // FIXME(#11621): Should be deprecated once CTFE is implemented in favour of
 // calling the `mem::size_of` function.
 #[unstable(feature = "core")]
-pub const BYTES : u32 = ($bits / 8);
+pub const BYTES : usize = ($bits / 8);
 
 // FIXME(#11621): Should be deprecated once CTFE is implemented in favour of
 // calling the `Bounded::min_value` function.
diff --git a/src/libcore/num/uint_macros.rs b/src/libcore/num/uint_macros.rs
index d0c4885ad00b..867829507455 100644
--- a/src/libcore/num/uint_macros.rs
+++ b/src/libcore/num/uint_macros.rs
@@ -13,9 +13,9 @@
 macro_rules! uint_module { ($T:ty, $T_SIGNED:ty, $bits:expr) => (
 
 #[unstable(feature = "core")]
-pub const BITS : u32 = $bits;
+pub const BITS : usize = $bits;
 #[unstable(feature = "core")]
-pub const BYTES : u32 = ($bits / 8);
+pub const BYTES : usize = ($bits / 8);
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub const MIN: $T = 0 as $T;