An absorbent article having a built-in size indicator is disclosed. The size indicator, for instance, comprises a stretchable panel that changes color when stretched. The panel may change color to indicate that the article is the correct size for the wearer or may change color to indicate that the article is too small. Still another embodiment, the stretchable panel may change from a first color indicating that the article is too large, to a second color that indicates the article is the correct size, and to a third color that indicates the article is too small. The stretchable panel may be made from any suitable color changing materials. For example, in one embodiment, the panel may include a gathered layer that is printed with a particular color only at the peaks of the gathered layer. As the gathered material is stretched, the material changes color due to the newly exposed regions. In other embodiments, the stretchable panel comprises a film that changes color when stretched. For example, the film may comprise a polyethylene that crystallizes when stretched or may comprise a polarized film that increases in polarization when stretched.