The keyhole neckline may be a simple slit in the neck of a blouse or dress. The split is usually, although not always, secured at its top with a hook and eye or loop and button. This kind of keyhole neckline is easy to make when sewing a garment, since the sewer only needs to finish the edges of the slit and secure it at the top. Most easy sewing patterns that include a "keyhole neckline" refer to this style.

The second, more complicated keyhole neckline looks more like its name. It is a circle or oval shape cut out of the neckline of a dress or top and secured, usually with a button and loop at the top. A circle or oval is difficult to cut properly, and the material must be well-marked for the keyhole neckline to look right.