diff --git a/src/wp-admin/includes/ajax-actions.php b/src/wp-admin/includes/ajax-actions.php
index 0f1f0f4e04..3441945217 100644
--- a/src/wp-admin/includes/ajax-actions.php
+++ b/src/wp-admin/includes/ajax-actions.php
@@ -4967,7 +4967,7 @@ function wp_ajax_health_check_site_status_result() {
 function wp_ajax_health_check_get_sizes() {
 	check_ajax_referer( 'health-check-site-status-result' );
 
-	if ( ! current_user_can( 'install_plugins' ) || is_multisite() ) {
+	if ( ! current_user_can( 'install_plugins' ) ) {
 		wp_send_json_error();
 	}
 
diff --git a/src/wp-admin/includes/class-wp-debug-data.php b/src/wp-admin/includes/class-wp-debug-data.php
index fe7fe60fef..ad4787c541 100644
--- a/src/wp-admin/includes/class-wp-debug-data.php
+++ b/src/wp-admin/includes/class-wp-debug-data.php
@@ -109,12 +109,10 @@ class WP_Debug_Data {
 			),
 		);
 
-		if ( ! $is_multisite ) {
-			$info['wp-paths-sizes'] = array(
-				'label'  => __( 'Directories and Sizes' ),
-				'fields' => array(),
-			);
-		}
+		$info['wp-paths-sizes'] = array(
+			'label'  => __( 'Directories and Sizes' ),
+			'fields' => array(),
+		);
 
 		$info['wp-dropins'] = array(
 			'label'       => __( 'Drop-ins' ),
@@ -391,10 +389,82 @@ class WP_Debug_Data {
 			);
 		}
 
-		// Remove accordion for Directories and Sizes if in Multisite.
-		if ( ! $is_multisite ) {
-			$loading = __( 'Loading…' );
+		if ( $is_multisite && get_site_option( 'upload_space_check_disabled' ) ) {
+			$uploads_quota = __( 'Unlimited' );
+		} elseif ( $is_multisite && is_main_site() ) {
+			$uploads_quota = sprintf(
+				// Translators: 1: The value of Site upload space.
+				__( '%s MB' ),
+				get_site_option( 'blog_upload_space', 100 )
+			);
+		} elseif ( $is_multisite ) {
+			$uploads_quota = sprintf(
+				// Translators: 1: The value of Site upload space.
+				__( '%s MB' ),
+				get_space_allowed()
+			);
+		}
+
+		if ( $is_multisite ) {
+			$max_upload_file_size = sprintf(
+				// Translators: 1: The value of Max upload file size.
+				__( '%s KB' ),
+				get_site_option( 'fileupload_maxk', 1500 )
+			);
+		}
 
+		$loading = __( 'Loading…' );
+
+		if ( ! $is_multisite ) {
+			$info['wp-paths-sizes']['fields'] = array(
+				'wordpress_path' => array(
+					'label' => __( 'WordPress directory location' ),
+					'value' => untrailingslashit( ABSPATH ),
+				),
+				'wordpress_size' => array(
+					'label' => __( 'WordPress directory size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+				'uploads_path'   => array(
+					'label' => __( 'Uploads directory location' ),
+					'value' => $upload_dir['basedir'],
+				),
+				'uploads_size'   => array(
+					'label' => __( 'Uploads directory size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+				'themes_path'    => array(
+					'label' => __( 'Themes directory location' ),
+					'value' => get_theme_root(),
+				),
+				'themes_size'    => array(
+					'label' => __( 'Themes directory size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+				'plugins_path'   => array(
+					'label' => __( 'Plugins directory location' ),
+					'value' => WP_PLUGIN_DIR,
+				),
+				'plugins_size'   => array(
+					'label' => __( 'Plugins directory size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+				'database_size'  => array(
+					'label' => __( 'Database size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+				'total_size'     => array(
+					'label' => __( 'Total installation size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+			);
+		} elseif ( $is_multisite && is_main_site() ) {
 			$info['wp-paths-sizes']['fields'] = array(
 				'wordpress_path' => array(
 					'label' => __( 'WordPress directory location' ),
@@ -414,6 +484,14 @@ class WP_Debug_Data {
 					'value' => $loading,
 					'debug' => 'loading...',
 				),
+				'uploads_quota'  => array(
+					'label' => __( 'Site upload space' ),
+					'value' => $uploads_quota,
+				),
+				'uploads_max_file_size' => array(
+					'label' => __( 'Max upload file size' ),
+					'value' => $max_upload_file_size,
+				),
 				'themes_path'    => array(
 					'label' => __( 'Themes directory location' ),
 					'value' => get_theme_root(),
@@ -443,6 +521,26 @@ class WP_Debug_Data {
 					'debug' => 'loading...',
 				),
 			);
+		} else {
+			$info['wp-paths-sizes']['fields'] = array(
+				'uploads_path'  => array(
+					'label' => __( 'Uploads directory location' ),
+					'value' => $upload_dir['basedir'],
+				),
+				'uploads_size'  => array(
+					'label' => __( 'Uploads directory size' ),
+					'value' => $loading,
+					'debug' => 'loading...',
+				),
+				'uploads_quota' => array(
+					'label' => __( 'Site upload space' ),
+					'value' => $uploads_quota,
+				),
+				'uploads_max_file_size' => array(
+					'label' => __( 'Max upload file size' ),
+					'value' => $max_upload_file_size,
+				),
+			);
 		}
 
 		// Get a list of all drop-in replacements.
@@ -1117,7 +1215,10 @@ class WP_Debug_Data {
 	 * @return array The sizes of the directories, also the database size and total installation size.
 	 */
 	public static function get_sizes() {
-		$size_db    = self::get_database_size();
+		if ( ! is_multisite() || is_multisite() && is_main_site() ) {
+			$size_db = self::get_database_size();
+		}
+
 		$upload_dir = wp_get_upload_dir();
 
 		/*
@@ -1143,12 +1244,18 @@ class WP_Debug_Data {
 
 		// Go through the various installation directories and calculate their sizes.
 		// No trailing slashes.
-		$paths = array(
-			'wordpress_size' => untrailingslashit( ABSPATH ),
-			'themes_size'    => get_theme_root(),
-			'plugins_size'   => WP_PLUGIN_DIR,
-			'uploads_size'   => $upload_dir['basedir'],
-		);
+		if ( ! is_multisite() || is_multisite() && is_main_site() ) {
+			$paths = array(
+				'wordpress_size' => untrailingslashit( ABSPATH ),
+				'themes_size'    => get_theme_root(),
+				'plugins_size'   => WP_PLUGIN_DIR,
+				'uploads_size'   => $upload_dir['basedir'],
+			);
+		} else {
+			$paths = array(
+				'uploads_size' => $upload_dir['basedir'],
+			);
+		}
 
 		$exclude = $paths;
 		unset( $exclude['wordpress_size'] );
@@ -1200,35 +1307,37 @@ class WP_Debug_Data {
 			$all_sizes[ $name ] = $results;
 		}
 
-		if ( $size_db > 0 ) {
-			$database_size = size_format( $size_db, 2 );
+		if ( ! is_multisite() || is_multisite() && is_main_site() ) {
+			if ( $size_db > 0 ) {
+				$database_size = size_format( $size_db, 2 );
 
-			$all_sizes['database_size'] = array(
-				'raw'   => $size_db,
-				'size'  => $database_size,
-				'debug' => $database_size . " ({$size_db} bytes)",
-			);
-		} else {
-			$all_sizes['database_size'] = array(
-				'size'  => __( 'Not available' ),
-				'debug' => 'not available',
-			);
-		}
+				$all_sizes['database_size'] = array(
+					'raw'   => $size_db,
+					'size'  => $database_size,
+					'debug' => $database_size . " ({$size_db} bytes)",
+				);
+			} else {
+				$all_sizes['database_size'] = array(
+					'size'  => __( 'Not available' ),
+					'debug' => 'not available',
+				);
+			}
 
-		if ( null !== $size_total && $size_db > 0 ) {
-			$total_size    = $size_total + $size_db;
-			$total_size_mb = size_format( $total_size, 2 );
+			if ( null !== $size_total && $size_db > 0 ) {
+				$total_size    = $size_total + $size_db;
+				$total_size_mb = size_format( $total_size, 2 );
 
-			$all_sizes['total_size'] = array(
-				'raw'   => $total_size,
-				'size'  => $total_size_mb,
-				'debug' => $total_size_mb . " ({$total_size} bytes)",
-			);
-		} else {
-			$all_sizes['total_size'] = array(
-				'size'  => __( 'Total size is not available. Some errors were encountered when determining the size of your installation.' ),
-				'debug' => 'not available',
-			);
+				$all_sizes['total_size'] = array(
+					'raw'   => $total_size,
+					'size'  => $total_size_mb,
+					'debug' => $total_size_mb . " ({$total_size} bytes)",
+				);
+			} else {
+				$all_sizes['total_size'] = array(
+					'size'  => __( 'Total size is not available. Some errors were encountered when determining the size of your installation.' ),
+					'debug' => 'not available',
+				);
+			}
 		}
 
 		return $all_sizes;