The short answer: Wrist monitors can be accurate, but they are less reliable in everyday use than upper-arm cuffs. In a 2026 Lausanne study, a validated wrist monitor read 9.8 mm Hg higher on average than an upper-arm monitor when people placed it themselves. Use one only when an arm cuff will not work.
How close are wrist monitors to upper-arm readings?
In controlled testing, wrist monitors look good. A 2020 conference abstract reviewed 29 validation studies. The mean difference from mercury readings was 0.47 mm Hg systolic and 0.17 mm Hg diastolic, and 93.1% of the monitors passed. This is an abstract, not a full paper, so treat it as a rough guide.
Home-style use looks different. In the Lausanne study, 121 adults placed two validated monitors themselves, using only the manuals. One was an Omron RS4 wrist monitor. The other was a Microlife WatchBP Home arm monitor. Wrist readings averaged 9.8 mm Hg higher systolic and 8.4 mm Hg higher diastolic. For a given person, the systolic gap could reach 44 mm Hg. The wrist monitor put 47.1% of people at or above 135 systolic, against 28.1% with the arm monitor. This was one wrist model with no position sensor, so it does not speak for every device.
A 2016 Italian study of 721 people points the same way. After training, people measured at home with a wrist monitor that had no position sensor, and with an arm monitor. At home, wrist readings ran 5.6% higher systolic and 5.4% higher diastolic than arm readings. Home measurement error reached at least 10 mm Hg in 455 people. The authors linked this to people forgetting the instructions and holding the wrist in the wrong position.
The picture improves when position is controlled. A 2016 BMJ Open review of people with obesity looked at wrist readings held at heart level. Against a correctly fitted arm cuff, sensitivity and specificity for hypertension were both 0.92. The mean systolic difference was only 0.51 mm Hg. But the limits of agreement ran from -21.7 to 22.6 mm Hg. The average can look fine while one person's reading is far off.
Why do wrist readings go wrong?
The 2019 American Heart Association statement names two problems, even for wrist devices that can measure accurately. First, the sensor must sit directly over the radial artery, and the monitor tends to shift. Bending the wrist can make this worse. Second, the wrist must be at heart level. Readings run too high if the wrist is below the heart and too low if it is above.
The US Validated Device Listing and the AHA give the wrist-specific rules:
- Place the device over the radial artery, as the manual shows.
- Hold the wrist at heart level for the whole reading.
- Keep movement and wrist bending to a minimum.
- Try resting your arm on a desk. The AHA says some users find this easier.
Our home monitoring guide covers everything else about taking a reading.
Position sensors help, but only partly. An 85-person study with Omron-affiliated authors tested the Omron RS6. Systolic readings came within 5 mm Hg of the reference for 65% of people with the sensor on, and 54% with it off.
Wrist cuffs also have size limits. One validated wrist model uses a single cuff for wrists of 12.5 to 21.5 cm, and the Lausanne study excluded wrists over 23 cm. Check your wrist size against the device instructions before you buy.
Who has a real reason to use a wrist monitor?
The Validated Device Listing says guidelines call for a validated upper-arm device. It adds that a validated wrist device may take its place in some cases:
- An upper-arm cuff does not suit your arm circumference.
- No device is available with the small, large, or extra-large cuff you need.
- You have a medical condition where an upper-arm device cannot or should not be used.
For very large arms, the AHA statement gives an order. Use a thigh cuff if the arm exceeds the largest arm cuff. If that does not fit, measure at the wrist. The BMJ Open review supports this: a wrong-size standard cuff had a sensitivity of 0.73 and a specificity of 0.76, worse than the wrist. Its authors say not to use an ill-fitting standard cuff.
Convenience is not on the list. The AHA notes strong reservations about routine wrist use unless upper-arm measurement is not feasible. It cannot recommend them for children, because no large studies exist. The international validation standard, ISO 81060-2:2018, treats pregnant women and children under 12 as special populations with their own requirements.
How do you check whether a wrist model is validated?
Search for the exact model number, then check these points:
- US list. Search validatebp.org. This list changed recently. Its October 2024 FAQ said wrist devices were not included. A March 2026 copy of the list shows 12 wrist devices among 151.
- International lists. A 2022 review of device lists says STRIDE BP considers wrist cuffs but labels upper-arm devices "Preferred." The British and Irish Hypertension Society list also includes wrist cuffs.
- What validated means. Under ISO 81060-2, the mean difference must be within 5 mm Hg, with a standard deviation within 8 mm Hg (2025 validation paper). That is a group result, not a promise for your wrist.
- Marketing claims. The same 2022 review warns that regulatory clearance is not the same as clinical validation.
Smartwatches are a separate topic. A 2026 European Society of Hypertension statement found only two watch-type cuff monitors with published validation to established standards. An AHA statement on cuffless devices says those on the market have not been adequately vetted for accuracy.
How do you test a wrist monitor against an arm cuff?
We found no pass mark written for wrist monitors. The closest is the AMA device accuracy test, a five-reading check run by a care team. A 2023 study of the test used only upper-arm monitors, so treat it as a borrowed standard. Bring your monitor to a visit and ask your care team to run it:
- Sit with feet flat, back supported, and arm at heart level. The 2023 study used a 5-minute rest and the same arm for every reading.
- Place the wrist monitor over the radial artery and hold it at heart level.
- Take reading A on your monitor. Discard it.
- Take reading B on your monitor, reading C on the office device, then reading D on your monitor.
- Average the systolic numbers from B and D. Compare that average to C and ignore any minus sign.
- If the gap is under 5 mm Hg, the AMA says the device can be used (the 2023 study also passed exactly 5). Over 10 mm Hg, replace it.
- If the gap is 6 to 10 mm Hg, take reading E on the office device. Average C and E, then compare that to D. A gap of 10 mm Hg or less passes.
- Repeat the test every year, or any time your readings seem questionable.
Write down diastolic numbers too. The AMA test uses systolic only. In the 2023 study, 22.4% of 152 upper-arm monitors failed, and 14% of those that passed missed the office diastolic reading by more than 10 mm Hg.
No source we read sets a pass mark for a home test against your own arm cuff. The same reading order gives a rough check if your arm cuff is validated. Use one arm throughout, because arms can differ.
The bottom line
A validated wrist monitor can read close to an arm cuff, but placement and wrist height decide the result. Studies of people using them alone show readings that run high. If an arm cuff fits you, use it. If none does, pick a listed wrist model that fits your wrist, then have it tested.
Do not assume a very high wrist reading is a position error. See what to do at 180 or above. If a reading comes with symptoms you cannot explain, symptom.md can help you think them through.
Last updated: November 2026. This article is for informational purposes only and does not constitute medical advice. Talk to your care team about which monitor suits you and whether your readings can be trusted.