First of all, find out the Page ID of the page to change the background color. To find out page ID, Go to Pages >All Pages then you will see the number in the format post=number in the URL.

Page ID

The displayed number is the Page ID for that page.

Now go to Appearance>Customize

Inside the customizer, you will be able to see Additional CSS towards the bottom left side. Open it to place your code to change the background color.

Customizing Additional CSS

Paste this code in the additional CSS to change the background color of that page.

body.page.page-id-AA {

background-color: BB;

}

Here AA represents the page ID while BB represents the color code.  Finally, publish the code after you are ready with the additional CSS.

Now to verify the changes, open the particular page in a new tab or in an incognito mode just to prevent any cache if present. You can also hard refresh and view the page in the same tab.

Background Color Changed

Boom! The changes are seen as desired.

Summary

If you have followed this post, you know how to change the background color of a single page in WordPress. In conclusion, follow these steps:

1. Log in to the dashboard and find the Page ID in WordPress in the URL.
2. Select the appropriate color for that page.
3. Go to Appearance>Customize>Additional CSS
4. Place the background-color code and publish.