diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs
index a171f128c24d6..9da7f8711c288 100644
--- a/src/liballoc/collections/binary_heap.rs
+++ b/src/liballoc/collections/binary_heap.rs
@@ -165,6 +165,10 @@ use super::SpecExtend;
 /// trait, changes while it is in the heap. This is normally only possible
 /// through `Cell`, `RefCell`, global state, I/O, or unsafe code.
 ///
+/// The costs of `push` and `pop` and `peek` can be performed in `O(1)` time.
+/// Note that these are non-amortized costs. The amortized cost for `push`
+/// and `pop` are `O(log(N))` due to re-allocations and maintaining the heap property.
+///
 /// # Examples
 ///
 /// ```