While both of these products provide an even and smooth tone to your skin, there are some striking differences between the two. The major difference is in the way they are supposed to be used. Foundation covers the entire face and neck while concealers only on specific areas like dark circles and pimples. You can use concealers with or without foundation depending on the finish you want. Foundations will only come in shades of different skin tones. But concealers come in a few different colours apart from the shades of natural skin tone.