diff --git a/typings/xterm-headless.d.ts b/typings/xterm-headless.d.ts
index b2ad5745..40034607 100644
--- a/typings/xterm-headless.d.ts
+++ b/typings/xterm-headless.d.ts
@@ -156,7 +156,7 @@ declare module '@xterm/headless' {
     /**
      * The amount of scrollback in the terminal. Scrollback is the amount of
      * rows that are retained when lines are scrolled beyond the initial
-     * viewport.
+     * viewport. Defaults to 1000.
      */
     scrollback?: number;
 
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index d957d655..a46db4be 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -225,7 +225,7 @@ declare module '@xterm/xterm' {
     /**
      * The amount of scrollback in the terminal. Scrollback is the amount of
      * rows that are retained when lines are scrolled beyond the initial
-     * viewport.
+     * viewport. Defaults to 1000.
      */
     scrollback?: number;