diff --git a/packages/react-select/src/internal/RequiredInput.tsx b/packages/react-select/src/internal/RequiredInput.tsx
index 834dfca3b3..00d2c1588f 100644
--- a/packages/react-select/src/internal/RequiredInput.tsx
+++ b/packages/react-select/src/internal/RequiredInput.tsx
@@ -21,6 +21,7 @@ const RequiredInput: FunctionComponent<{
       left: 0,
       right: 0,
       width: '100%',
+      boxSizing: 'border-box',
     }}
     // Prevent `Switching from uncontrolled to controlled` error
     value=""