The Visual Analog Scale (VAS) for pain is one of the simplest and most widely used measures of pain intensity. This page explains what the VAS is, what it measures, how it is administered, how it is scored, and how it is used.
What is the VAS for pain?
The Visual Analog Scale (VAS) for pain is a single-item, self-reported measure of pain intensity. It presents a straight line, usually 100 mm long, anchored at one end by "no pain" and at the other by "worst pain imaginable." The patient marks the point on the line that represents their current pain. Versions of the VAS have been used for more than a century and it remains one of the most common pain-intensity measures in research and clinical care.
What does the VAS measure?
The VAS measures the intensity of a patient's pain as a continuous value, capturing subtle differences that categorical scales may miss. It is used for both acute and chronic pain and is well suited to tracking changes in pain over time.
What does the VAS include?
The instrument consists of a single line, typically 100 mm, with descriptive anchors at each end (for example, "no pain" and "worst pain"). The patient places a single mark perpendicular to the line at the position that best reflects their pain. Clear instructions to rate current pain, rather than usual or average pain, help ensure consistent responses.
How is the VAS scored?
Scoring is done by measuring the distance in millimeters from the "no pain" end of the line to the patient's mark, producing a score from 0 to 100 (or 0 to 10 cm). A higher score indicates more intense pain. Published research on postoperative pain has suggested interpretive bands of roughly 0 to 4 mm for no pain, 5 to 44 mm for mild pain, 45 to 74 mm for moderate pain, and 75 to 100 mm for severe pain, and a reduction of about 30% is often considered a clinically meaningful improvement.
How is the VAS used in clinical practice?
The VAS is used to record pain at a single point in time and to monitor how pain changes with treatment. It takes less than a minute to complete, requires only the ability to measure the mark with a ruler in the paper version, and is often collected alongside function-focused PROMs so that both pain and function can be tracked. Digital versions can automate the measurement.
Strengths and limitations
Strengths include simplicity, speed, sensitivity to small changes, and broad validation. Limitations include the need to physically measure the mark in paper versions, the fact that it captures only pain intensity and not other dimensions such as function or interference, and that the paper format cannot be administered verbally. It is best used together with other measures for a complete clinical picture.
Frequently asked questions
How long is the VAS line? It is usually a 100 mm horizontal line anchored by "no pain" and "worst pain."
How is a VAS score calculated? By measuring the distance from the "no pain" end to the patient's mark, giving a score from 0 to 100 mm.
What VAS change is meaningful? A reduction of about 30% from baseline is commonly considered clinically relevant.
References
- Jensen MP, Chen C, Brugger AM. Interpretation of visual analog scale ratings and change scores: a reanalysis of two clinical trials of postoperative pain. Journal of Pain. 2003;4(7):407-414.
- Hawker GA, Mian S, Kendzerska T, French M. Measures of adult pain: VAS for Pain, NRS for Pain, and others. Arthritis Care & Research. 2011;63(S11):S240-S252.
- Bijur PE, Silver W, Gallagher EJ. Reliability of the visual analog scale for measurement of acute pain. Academic Emergency Medicine. 2001;8(12):1153-1157.
Note: This page is educational. Pain that is severe, worsening, or associated with other symptoms should be evaluated by a healthcare professional.
