diff --git a/2018-edition/src/ch03-02-data-types.md b/2018-edition/src/ch03-02-data-types.md
index 86359ea809..d0fe0cc2be 100644
--- a/2018-edition/src/ch03-02-data-types.md
+++ b/2018-edition/src/ch03-02-data-types.md
@@ -173,6 +173,8 @@ The main way to consume Boolean values is through conditionals, such as an `if`
 expression. We’ll cover how `if` expressions work in Rust in the “Control Flow”
 section.
 
+Booleans are one byte in size.
+
 #### The Character Type
 
 So far we’ve worked only with numbers, but Rust supports letters too. Rust’s