diff --git a/src/backends/native/meta-monitor-manager-kms.c b/src/backends/native/meta-monitor-manager-kms.c
index cc2b18eb2..1a2338db9 100644
--- a/src/backends/native/meta-monitor-manager-kms.c
+++ b/src/backends/native/meta-monitor-manager-kms.c
@@ -496,8 +496,18 @@ meta_monitor_manager_kms_read_current (MetaMonitorManager *manager)
       meta_mode->name = g_strndup (mode->name, DRM_DISPLAY_MODE_LEN);
       meta_mode->width = mode->hdisplay;
       meta_mode->height = mode->vdisplay;
-      meta_mode->refresh_rate = (1000 * mode->clock /
-                                 ((float)mode->htotal * mode->vtotal));
+
+      /* Calculate refresh rate in milliHz first for extra precision. */
+      meta_mode->refresh_rate = (mode->clock * 1000000LL) / mode->htotal;
+      meta_mode->refresh_rate += (mode->vtotal / 2);
+      meta_mode->refresh_rate /= mode->vtotal;
+      if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+	meta_mode->refresh_rate *= 2;
+      if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
+        meta_mode->refresh_rate /= 2;
+      if (mode->vscan > 1)
+        meta_mode->refresh_rate /= mode->vscan;
+      meta_mode->refresh_rate /= 1000.0;
 
       meta_mode->driver_private = g_slice_dup (drmModeModeInfo, mode);
       meta_mode->driver_notify = (GDestroyNotify)meta_monitor_mode_destroy_notify;
diff --git a/src/wayland/meta-wayland-outputs.c b/src/wayland/meta-wayland-outputs.c
index 1a7d16efa..df199499f 100644
--- a/src/wayland/meta-wayland-outputs.c
+++ b/src/wayland/meta-wayland-outputs.c
@@ -99,7 +99,7 @@ bind_output (struct wl_client *client,
                        mode_flags,
                        (int)monitor_info->rect.width,
                        (int)monitor_info->rect.height,
-                       (int)monitor_info->refresh_rate);
+                       (int)(monitor_info->refresh_rate * 1000));
 
   if (version >= WL_OUTPUT_SCALE_SINCE_VERSION)
     wl_output_send_scale (resource, output->scale);
@@ -160,7 +160,7 @@ wayland_output_update_for_output (MetaWaylandOutput *wayland_output,
                            mode_flags,
                            (int)monitor_info->rect.width,
                            (int)monitor_info->rect.height,
-                           (int)monitor_info->refresh_rate);
+                           (int)(monitor_info->refresh_rate * 1000));
     }
 
   /* It's very important that we change the output pointer here, as