Frequently asked questions

What does the Moodmetric ring measure?

The Moodmetric ring detects sympathetic nervous system activation. High activation means positive or negative stress, low activation calmness/relaxation.

The sympathetic nervous system activation is understood by measuring electrodermal activity (EDA)  – also known as galvanic skin response (GSR) or skin conductance response (SCR).

The Moodmetric smart ring is designed to measure EDA accurately. The Moodmetric algorithm interprets the raw data with an easy to understand index from 1 to 100. This index is robust to motional artefacts and is comparable among different wearers.

What is electrodermal activity (EDA)?

Measurement of electrodermal activity is widely adopted in psychological studies. The activation of autonomic nervous system can be measured from skin conductivity.

A strong autonomic nervous system (ANS) reaction is the so called fight-or-flight response: a person sees, hears or experiences something that needs an action. This reaction is sub-conscious and in the early times of human history reserved for life-threatening situations.

Today, many people are in the heightened state of alertness continuously – they experience stress. Also positive stress can wear out when it keeps a person active for long periods of time, without proper recovery.

Read more

What is the physiological mechanism behind EDA?

The skin on the palmar of a hand has a high density of sweat glands that react with any signal of the sympathetic autonomic nervous system. These reactions ultimately make the hands sweat, and the skin conductivity increases. This phenomen is electrodermal activity and can be best measured from palm or fingers.

Does the Moodmetric ring  measure heart rate?

No, there is no measurement of heart rate, nor heart rate variability.

Is the Moodmetric measurement accurate?

Yes, the measurement signal has been verified by the Finnish Institute of Occupational Health. The ring is valid for field research.

Why a ring and not a wrist device?

The skin conductivity measurement requires high density of so called eccrine sweat glands. To get an accurate measurement it has to be done from highest density areas: palms of a hand or fingers, or soles of feet. Read more here.

Does the moodmetric ring tell about wearer´s mood?

No, the measurement does not indicate mood. It does not tell which specific emotion the wearer is experiencing. The Diary feature in the Moodmetric app gives a possibility to indicate positive of negative mood in relation to certain calendar event.

Can several people use one Moodmetric ring?

The ring is meant to be personal. It has a  learning algorithm that adjusts to one user in about 12 hours.

When changing from one user to another, the calibration time needs to be considered: during the first hours the measurement results tend to be closed to median (50) than later on.

The ring can is used for instance to user experience testing, where wearer´s change continuously and wearing times are short. In these cases at least 30 minutes calibration time should be allowed and the wearer should both try and relax properly and get excited during that time. This enhances calibration and makes the test more accurate.

How do I start using my Moodmetric ring?

Why and how the ring is calibrated?

The Moodmetric measurement result 1-100 is defined by an algorithm that adjusts to the wearer. In practice this means that the lowest possible level (1) is reached in deep sleep, and the maximum (100) e.g. when really frightened. When the ring has been measuring at least for several hours, has the wearer max and min been detected, and set as personal limits. After this the measurement results are accurate and always show typical levels for the user. This happens at latest after 24 hours, often much sooner.

Adjusting to user starts when tapping the ‘Calibrate’-button on the Moodmetric mobile app. The ring needs to be worn at this stage, as otherwise the app does not detect the ring and calibration can not be done.

The one and the same user only needs to calibrate the ring once, when taking a new ring to use. Doing the calibration again would re-start the adjusting from the beginning, so that is not adviced.

Note: The Calibrate-button goes red for a second with the Android and pale/gray with the iOS phones, when tapping it. This might go unnoticed. You will know that the calibration is done, when while returning to main screen, the MM level is 50 for a moment. The level goes on changing immediately after. 

Are measurement results between users comparable?

Yes. The Moodmetric index learns the base line of the user and gives 100 for the detected maximum reaction and 1 for the minimum. Lowest reaction typically occurs in deep sleep and maximum in a very exciting or frightening situation.
When two persons each have their app showing 100, they are both in their maximum alertness level.

How the measurement results can be interpreted?

Please refer to this article:

How to interpret the Moodmetric data

How does Moodmetric send the data from the ring to the phone?

The ring uses Bluetooth Smart to communicate with your smartphone.

Do I need to keep my phone close to the ring?

No. The ring works standalone and stores the data up to 270 hours. The data can be downloaded whenever you open the app. It is however adviced to download the data from the ring to the phone at least once per day.

Do i need to use the ring continuously?

To get the most out of your Moodmetric ring and its data, use the ring continuously, day and night. You can also use the ring for a set time period.

Lack of use might result in the battery draining out and not charging optimally anymore. Make sure that if the ring is unused for more than 4 weeks, it is charged regularly, at least once a month.

Is the ring waterproof?

No. It is only splash proof.

What if there is no measurement signal?

If the measurement signal does not appear on the app, or the app does not find the ring, check the following:

    • bluetooth is turned ON on the device
    • location services are turned ON (on Android phones)
    • the ring is charged
    • the phone charging level is at least 20%
    • when going to Menu, your ring appear
    • if your hands are very dry or cold, try and add some moisturizer for a better skin contact
    • cold hands with a ring that is slightly too big, can cause breaking connection

You can also

  • In Menu, check that the ring is connected. “Forget” should be seen on lower left corner. If not, press Connect to establish the connection.
  • Try to turn the bluetooth OFF and back ON
  • Shut down the app and open it up again
  • Plug the ring and lightly touch the band and while doing so, try to find the ring with the app (the ring signal is stronger once in charger)
  • With Android phones it can take some time to form a connection. What up to 1 minute.
  • If location services have been turned off, you need to re-start the phone.
Does Bluetooth need to be on at the device always?

No, you can keep BT off, except when downloading data from the ring to the device, or when you follow the real-time signal on the phone.

Note, that if BT has been turned off, you might need to refresh the connection when going to the app: choose Menu, choose your ring until the Ring details screen opens. Verify that the ring is connected with the phone (when connected, it says ‘Forget’ at the bottom left corner.

How do I find the right ring size?

The Moodmetric ring comes in five sizes:

XS – 16mm – US5.5
S – 17mm – US6
M – 18.5mm – US8.5
L – 20mm – US 10
XL – 21.5mm – US 12

The ring can be worn in any finger except the thumb. It can also be changed from one finger to another, e.g. at night it is good to put it to a finger where it a loose –> the fingers normally swell a bit during the night.

Note that the finger sizes are different in the right and left hand, this facilitates in finding the best fit.

The right size can be found by measuring inner diameter of an existing ring or using a sizing chart, for example

For researchers who are planning several rings for a studied population:
Size M fits most women and L most men. If researchers order several sizes, we normally advice followingly:
20% of size 17mm
30% of size 18.5mm
30% of size 20mm
20% of size 21.5mm
(Size XS only if there are people with very small hands among the group).
The band of the ring can not be detached / swapped. For each size, a different ring is needed.

Important! If you suffer from excess swelling of the hands, please consider the usage carefully.

Where can I download the app?

From App Store  and Google Play.

Is the Moodmetric app compatible with all phone models?

The Moodmetric app works in iOS and Android phones that are bluetooth4 compatible.

Apple iPhone: 4S and later models

Apple iPad:

iPad, 3rd generation
iPad, 4th generation
iPad mini
iPad mini 2
iPad mini 3
iPad Air
iPad Air 2

and later models

The Moodmetric app is available for almost all the Android phones. Some models however are not compatible. Prior to ordering a Moodmetric ring, check that the Moodmetric app is available at your phone Google Play and that you can donwload it.

Even though the download would be succesfull, there might be issues with the phone – ring connectivity with some Android phones.

At the moment for instance Samsung Galaxy A3 can not connect to your Moodmetric ring.

Cloud service

The cloud service is for backing up the measurement data at your mobile device. It is also a convenient way to follow stress levels on long term and to draw excel and csv reports of your data.

Accessing the cloud service is not mandatory.  After purchasing the ring, you can request credentials at

First login from your (desktop) browser and then with the same credentials from the app. Those not wanting to use the cloud, can simply choose “Use without cloud access” from the app.

Note: Possible login errors might be due to chosen browser. We recommend Chrome and Firefox to access Moodmetric Cloud.

Are you interested in the cloud interface and viewing the Moodmetric data on your own platform via Moodmetric API? Please contact us: [email protected]

Do you have a Developer Kit?

Yes, the Moodmetric Software Developer Kit is available. Inquiries: [email protected]


Apart from stress, What might cause higher or lower Moodmetric levels than what I normally get?


Chronic illness

A serious medical condition often means unbalanced autonomic nervous system. Very high or very low Moodmetric levels can be detected.  Medication and other treatments play a big role with long term illnesses and equally affect the Moodmetric levels (see also the next point).


Especially strong medication might affect the balance of the autonomic nervous system. The Moodmetric measurement can then detect abnormal levels.