diff --git a/CHANGELOG.md b/CHANGELOG.md
index 23f10509..2ad375d3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,11 @@
 ### Deprecated
 ### Removed
 ### Fixed
+
+* Crash when bitmap fonts are scaled down to very small font sizes
+  (https://codeberg.org/dnkl/foot/issues/830).
+
+
 ### Security
 ### Contributors
 
diff --git a/terminal.c b/terminal.c
index 1d27693a..d5728a53 100644
--- a/terminal.c
+++ b/terminal.c
@@ -688,6 +688,11 @@ term_set_fonts(struct terminal *term, struct fcft_font *fonts[static 4])
         : max(term->fonts[0]->height,
               term->fonts[0]->ascent + term->fonts[0]->descent);
 
+    if (term->cell_width <= 0)
+        term->cell_width = 1;
+    if (term->cell_height <= 0)
+        term->cell_height = 1;
+
     term->font_x_ofs = term_pt_or_px_as_pixels(term, &conf->horizontal_letter_offset);
     term->font_y_ofs = term_pt_or_px_as_pixels(term, &conf->vertical_letter_offset);