Free blood pressure machines: Are they accurate?

Medically reviewed by Drugs.com. Last updated on Apr 28, 2022.

Public blood pressure kiosk machines, such as those found in pharmacies, may provide helpful information about your blood pressure. But public blood pressure machines can have limitations too. Their accuracy depends on many things, including correct cuff size and proper use. Ask your health care provider for advice on using public blood pressure machines.

It's important that the blood pressure cuff fits you well. The cuff is the band that goes around the upper arm. The cuffs on some public blood pressure machines may be too small or too large for some people. Using a blood pressure cuff that's too large or too small may give you an inaccurate blood pressure reading. So, you might think your blood pressure is fine when it's not.

Some machines measure blood pressure using a wrist cuff. A wrist blood pressure device may be as accurate as an upper arm monitor, but it needs to be fitted properly and checked with readings taken in a provider's office. A wrist blood pressure monitor must be placed directly over the wrist (radial) artery to get an accurate reading. The wrist must be positioned at heart level. Flexing the wrist can cause incorrect readings.

Another concern is that some public blood pressure machines aren't standardized, which makes it hard to know how accurate they are.

It's best to have your blood pressure checked by a trained health care provider using an accurate instrument. When considering if you have low or high blood pressure, your provider should consider the average of two or more blood pressure readings from three or more office visits.

If you need more frequent blood pressure checks, your health care provider can tell you how to monitor your blood pressure at home. Home blood pressure monitoring can be a convenient way to get regular blood pressure readings. Ask your provider to check your device for a proper fit and accuracy.

Don't stop or change your medications or alter any diet changes you've made without talking to your provider first, even if your home readings seem OK. Grocery store and pharmacy testing and home blood pressure monitoring aren't substitutes for regular health checkups.