diff --git a/core/modules/responsive_image/src/ResponsiveImageStyleForm.php b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
index 4240473900..c2fd9e1cd4 100644
--- a/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
+++ b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
@@ -156,8 +156,9 @@ public function form(array $form, FormStateInterface $form_state) {
           ],
         ];
         $form['keyed_styles'][$breakpoint_id][$multiplier]['sizes'] = [
-          '#type' => 'textfield',
+          '#type' => 'textarea',
           '#title' => $this->t('Sizes'),
+          '#maxlength' => NULL,
           '#default_value' => isset($image_style_mapping['image_mapping']['sizes']) ? $image_style_mapping['image_mapping']['sizes'] : '100vw',
           '#description' => $this->t('Enter the value for the sizes attribute, for example: %example_sizes.', ['%example_sizes' => '(min-width:700px) 700px, 100vw']),
           '#states' => [