diff --git a/crates/typst/src/layout/spacing.rs b/crates/typst/src/layout/spacing.rs
index 571cc8704..60e9b59bc 100644
--- a/crates/typst/src/layout/spacing.rs
+++ b/crates/typst/src/layout/spacing.rs
@@ -18,7 +18,8 @@ use crate::utils::Numeric;
 ///
 /// # Mathematical Spacing { #math-spacing }
 /// In [mathematical formulas]($category/math), you can additionally use these
-/// constants to add spacing between elements: `thin`, `med`, `thick`, `quad`, `wide`.
+/// constants to add spacing between elements: `thin` (1/6 em), `med`(2/9 em),
+/// `thick` (5/18 em), `quad` (1 em), `wide` (2 em).
 #[elem(title = "Spacing (H)", Behave)]
 pub struct HElem {
     /// How much spacing to insert.