Do BP readings differ between arms? Doctor explains what it means

You’re sitting in the doctor’s office, they slap the cuff on your right arm, pump it up, and read out your blood pressure. But then they decide to check the left arm too… and wait a minute the numbers don’t match. Cue the little voice in your head: Is something wrong?

Let’s talk about why this happens, when it’s totally fine, and when it might be a sign to dig deeper.

Yep, it’s normal… sometimes

First, don’t panic. Small differences in blood pressure between your two arms are actually pretty common. In fact, for most healthy people, it’s normal to see a difference of up to 10 mmHg (that’s millimeters of mercury, the unit for BP).

So if your right arm says 122/78 and your left says 128/80, you can probably relax, it’s likely just normal variation.

When the difference could mean something more
Now, here’s the important bit, according to Harvard Health, if there’s a consistent difference of more than 10–15 mmHg between your arms, especially in the top (systolic) number, it’s worth talking to your doctor.

Larger, ongoing differences can sometimes be linked to:

Artery narrowing (Peripheral Artery Disease) – If one arm has a partially blocked artery, it can affect blood flow and pressure readings.

Aortic dissection (rare, but serious) – This is a sudden tear in the aorta wall. It’s an emergency and comes with other severe symptoms like chest pain.

Recently, Dr Sudhir Kumar took to X to explain this phenomenon. "1. Variation of systolic BP up to 10 mmHg and diastolic BP of up to 5 mmHg between two arms is normal. Always use the higher arm reading for recording. 2. If the inter-arm variation is greater than 15 mmHg, it is NOT normal- could be suggestive of a vascular disease- get evaluated by a doctor," he posted on X.

Can the BP readings be different in two arms- right and left?

1. Variation of systolic BP up to 10 mmHg and diastolic BP of up to 5 mmHg between two arms is normal. Always use the higher arm reading for recording.
2. If the inter-arm variation is greater than 15 mmHg, it is NOT… https://t.co/LMUczqf4Nn

— Dr Sudhir Kumar MD DM (@hyderabaddoctor) August 14, 2025

Why doctors sometimes check both arms
Medical pros know that arm-to-arm BP differences can reveal hidden circulation issues. That’s why many guidelines suggest measuring both arms at least once during checkups, especially for new patients or anyone at higher cardiovascular risk.

If one arm consistently shows higher readings, your doctor might recommend using that arm for all future measurements to keep your numbers consistent.

What you can do at home

If you’ve got a blood pressure monitor at home (and honestly, they’re a great investment if you care about heart health), here’s how to check:

Measure both arms – Sit quietly for 5 minutes, then check your BP on one arm, rest for a minute, and check the other.

Keep a log – Write down your readings and any noticeable patterns.

Talk to your doctor – If the difference is consistently over 10–15 mmHg, bring your log to your next appointment.

A small difference in blood pressure between arms? Totally normal. But if you’re seeing a bigger, consistent gap, don’t ignore it—it could be your body’s way of flagging something important.

Your arms might look the same on the outside, but the blood vessels inside could be telling two different stories. Checking both arms every once in a while is a simple, quick way to keep an eye on your circulation health.

Next time a nurse or doctor checks your BP, you’ll know exactly why they sometimes switch sides. Not because they’re bored… but because your arms might be trying to tell them something.