A pain scale is a tool that doctors use to help assess a person’s pain. A person usually self-reports their pain using a specially designed scale, sometimes with the help of a doctor, parent, or guardian. Pain scales may be used during admission to a hospital, during a doctor visit, during physical activity, or after surgery.

Doctors use the pain scale to better understand certain aspects of a person’s pain. Some of these aspects are pain duration, severity, and type.

Pain scales can also help doctors make an accurate diagnosis, create a treatment plan, and measure the effectiveness of treatment. Pain scales exist for people of all ages, from newborns to seniors, as well as people with impaired communication skills.

There are two categories that include several types of pain scales.

Unidimensional pain scales

These pain scales are a simple way for people to rate the intensity of their pain. They use words, images, or descriptors to measure pain or pain relief. Some common unidimensional pain scales include:

Numeric rating scales (NRS)

This pain scale is most commonly used. A person rates their pain on a scale of 0 to 10 or 0 to 5. Zero means “no pain,” and 5 or 10 means “the worst possible pain.”

These pain intensity levels may be assessed upon initial treatment, or periodically after treatment.

Visual analog scale (VAS)

This pain scale shows a 10-centimeter line printed on a piece of paper, with anchors at either end. At one end is “no pain,” and at the other end are “pain as bad as it could be” or “the worst imaginable pain.”

The person marks a spot or X on the line to show their pain intensity. A doctor then measures the line with a ruler to come up with a pain score.

Categorical scales

These pain scales give people a simple way to rate their pain intensity using a verbal or visual descriptor of their pain. Some examples would be the words “mild,” “discomforting,” “distressing,” “horrible,” and “excruciating.”

For children, pain scales using images of faces are commonly used. A child may be presented with the images of eight different faces with various expressions. The child chooses the face that they feel is most consistent with their current pain level.

Multidimensional tools

Multidimensional tools for pain assessment aren’t always commonly used. However, many experts argue that they’re extremely valuable, just underused. Some examples include:

Initial pain assessment tool

This tool is designed for use during an initial evaluation. It helps a doctor get information from the person about the characteristics of their pain, the way the person expresses their pain, and how the pain is affecting the person’s everyday life.

This pain scale includes the use of a paper diagram. It shows a body where people can mark the location of their pain, as well as a scale to rate pain intensity and a space for more comments. See an example of the assessment tool here.

Brief pain inventory (BPI)

This tool is very fast and simple for people to use to help measure pain intensity and associated disability. It includes a series of questions addressing aspects of pain felt over the previous 24 hours. See an example of this tool here.

McGill pain questionnaire (MPQ)

This is one of the most widely used multidimensional pain scales. It appears in questionnaire form, and assesses a person’s pain based on the words they use to describe their pain. See an example of this tool here.

Pain scales can be useful in assessing a person’s acute, or sudden, pain. However, these tools can sometimes oversimplify the pain assessment process.

Pain can be multidimensional. It can have different characteristics and affect different parts of a person’s life. Because of this, multidimensional pain scales are among the most useful and effective when used to assess complex or chronic (long-term) pain.