The present invention is a portable gauge made up of a elongated body and a slider. The body includes gauge marks, based on a specific bucket, to indicate various levels of liquid volume. The body includes an upper end, which has downwardly directed integrally formed arms which, in combination with the body, define a saddle. The saddle is sized and shaped to comfortably capture and rest on the rim of the bucket, during use. The slider is sized and shaped to snuggly slide along the body and includes a tab portion. A plurality of detents located along the length of the body engagingly cooperate with a spring-biased tab on the slider to provide controlled interval movement of the slider with respect to the body.In use, the user simple holds the body comfortably in front of his or her face and slides the slider along the body until the tab portion aligns with a desired gauge mark. The plurality of detents and the slider tab help retain the position of the slider, as the user places the body into a bucket so that the body resides along the inside wall of the bucket and so that the saddle at the upper portion of the body engages with the rim of the bucket. The user may then add liquid to the bucket, as desired, until the level of the liquid aligns with the tab portion of the slider, at which point the volume of liquid within the bucket would equal the volume indicated by the slider and the aligned gauge mark. The user could then simple remove the body from the bucket.