diff --git a/crates/typst-layout/src/inline/shaping.rs b/crates/typst-layout/src/inline/shaping.rs
index 6e77a80e7..2a1fc8586 100644
--- a/crates/typst-layout/src/inline/shaping.rs
+++ b/crates/typst-layout/src/inline/shaping.rs
@@ -1044,9 +1044,8 @@ fn calculate_adjustability(ctx: &mut ShapingContext, lang: Lang, region: Option<
 
 /// Difference between non-breaking and normal space.
 fn nbsp_delta(font: &Font) -> Option<Em> {
-    let space = font.ttf().glyph_index(' ')?.0;
     let nbsp = font.ttf().glyph_index('\u{00A0}')?.0;
-    Some(font.advance(nbsp)? - font.advance(space)?)
+    Some(font.advance(nbsp)? - font.space_width()?)
 }
 
 /// Returns true if all glyphs in `glyphs` have ranges within the range `range`.
diff --git a/crates/typst-layout/src/math/mod.rs b/crates/typst-layout/src/math/mod.rs
index b18bd98d0..5fd22e578 100644
--- a/crates/typst-layout/src/math/mod.rs
+++ b/crates/typst-layout/src/math/mod.rs
@@ -373,7 +373,6 @@ struct MathContext<'a, 'v, 'e> {
     // Font-related.
     font: &'a Font,
     constants: ttf_parser::math::Constants<'a>,
-    space_width: Em,
     // Mutable.
     fragments: Vec<MathFragment>,
 }
@@ -386,15 +385,10 @@ impl<'a, 'v, 'e> MathContext<'a, 'v, 'e> {
         base: Size,
         font: &'a Font,
     ) -> Self {
-        let math_table = font.ttf().tables().math.unwrap();
-        let constants = math_table.constants.unwrap();
-
-        let ttf = font.ttf();
-        let space_width = ttf
-            .glyph_index(' ')
-            .and_then(|id| ttf.glyph_hor_advance(id))
-            .map(|advance| font.to_em(advance))
-            .unwrap_or(THICK);
+        // These unwraps are safe as the font given is one returned by the
+        // find_math_font function, which only returns fonts that have a math
+        // constants table.
+        let constants = font.ttf().tables().math.unwrap().constants.unwrap();
 
         Self {
             engine,
@@ -402,7 +396,6 @@ impl<'a, 'v, 'e> MathContext<'a, 'v, 'e> {
             region: Region::new(base, Axes::splat(false)),
             font,
             constants,
-            space_width,
             fragments: vec![],
         }
     }
@@ -501,7 +494,8 @@ fn layout_realized(
     if let Some(elem) = elem.to_packed::<TagElem>() {
         ctx.push(MathFragment::Tag(elem.tag.clone()));
     } else if elem.is::<SpaceElem>() {
-        ctx.push(MathFragment::Space(ctx.space_width.resolve(styles)));
+        let space_width = ctx.font.space_width().unwrap_or(THICK);
+        ctx.push(MathFragment::Space(space_width.resolve(styles)));
     } else if elem.is::<LinebreakElem>() {
         ctx.push(MathFragment::Linebreak);
     } else if let Some(elem) = elem.to_packed::<HElem>() {
diff --git a/crates/typst-library/src/text/font/mod.rs b/crates/typst-library/src/text/font/mod.rs
index afa92e778..b2afb0466 100644
--- a/crates/typst-library/src/text/font/mod.rs
+++ b/crates/typst-library/src/text/font/mod.rs
@@ -113,6 +113,11 @@ impl Font {
             .map(|units| self.to_em(units))
     }
 
+    /// Look up the width of a space.
+    pub fn space_width(&self) -> Option<Em> {
+        self.0.ttf.glyph_index(' ').and_then(|id| self.advance(id.0))
+    }
+
     /// Lookup a name by id.
     pub fn find_name(&self, id: u16) -> Option<String> {
         find_name(&self.0.ttf, id)