diff --git a/runtime/ops/tty.rs b/runtime/ops/tty.rs
index 4b19fea9a9..5b49e3a248 100644
--- a/runtime/ops/tty.rs
+++ b/runtime/ops/tty.rs
@@ -351,10 +351,20 @@ fn console_size_from_fd(
     {
       return Err(Error::last_os_error());
     }
-    Ok(ConsoleSize {
-      cols: bufinfo.srWindow.Right as u32 - bufinfo.srWindow.Left as u32 + 1,
-      rows: bufinfo.srWindow.Bottom as u32 - bufinfo.srWindow.Top as u32 + 1,
-    })
+
+    // calculate the size of the visible window
+    // * use over/under-flow protections b/c MSDN docs only imply that srWindow components are all non-negative
+    // * ref: <https://docs.microsoft.com/en-us/windows/console/console-screen-buffer-info-str> @@ <https://archive.is/sfjnm>
+    let cols = std::cmp::max(
+      bufinfo.srWindow.Right as i32 - bufinfo.srWindow.Left as i32 + 1,
+      0,
+    ) as u32;
+    let rows = std::cmp::max(
+      bufinfo.srWindow.Bottom as i32 - bufinfo.srWindow.Top as i32 + 1,
+      0,
+    ) as u32;
+
+    Ok(ConsoleSize { cols, rows })
   }
 }