Terms of use

Who you are contracting with

Tonelva is operated by Vast Flow, LLP, Kunaeva 43, office 303, Almaty, Kazakhstan. "We", "us" and "our" mean Vast Flow, LLP. "The app" means the Tonelva mobile application on iOS and Android. "The site" means tonelva.com, including the free calculators published on it. By installing or using the app, or by using the site, you agree to these terms. If you do not agree with them, do not use the app or the site.

What we provide

A diary for blood pressure readings you take with your own cuff, tools that classify and average those readings against published reference standards, an optional fingertip pulse measurement that uses your phone's rear camera, and written reference material about home blood pressure monitoring. That is the entire scope of the service.

Tonelva does not measure blood pressure

Tonelva is not a medical device and it does not measure blood pressure. No phone can. Blood pressure measurement requires occluding an artery and detecting the pressure at which flow returns, and no phone has hardware that can do it — not the camera, not a fingertip on the screen, not a sensor of any kind. Every systolic and diastolic number in the app is one you entered from a validated cuff or imported from Apple Health.

This holds without exception, and it is worth being exact about it now that the app uses the camera for something else. The pulse feature described in the next section produces a heart rate and, for subscribers, beat-to-beat variability. It never produces, estimates, infers or suggests a systolic or diastolic value, at any confidence, under any label. The two live in separate screens with separate records and separate history, and the pulse result contains no blood pressure field at all. Any app that claims to read your blood pressure from a camera or a fingertip is measuring something else, or nothing.

Nothing in the app or on this site is medical advice, a diagnosis, or a recommendation about treatment. We do not tell you what your target should be, and we will not, because targets are individual and set by your clinician alongside everything else they know about you. We never suggest starting, stopping or changing a medication or a dose.

The categories the app and the tools display are published reference thresholds — the 2017 ACC/AHA classification and the ESC/ESH classification — applied to a number. A classification is not a diagnosis. Hypertension is diagnosed by a clinician from repeated readings, usually taken away from a clinic, interpreted together with your history and your overall cardiovascular risk. One reading, however alarming it looks, establishes nothing on its own.

The pulse measurement: what it is, and what it is not

The app can measure your pulse from a fingertip held over the rear camera with the camera's light on. The technique is photoplethysmography: light passing through the tip of your finger changes slightly with each heartbeat, and the timing of those changes gives a heart rate. A pulse measurement takes about thirty seconds and is free and unlimited. A longer measurement of about two minutes additionally reports heart rate variability — RMSSD, SDNN, pNN50 and the mean interval between beats — and is part of the Pro subscription.

It is a consumer wellness measurement, not a clinical one. Accuracy depends on things neither we nor you fully control: how still your hand is, how warm your hands are, how much of the lens your fingertip covers, the circulation at your fingertip, and the camera in your particular phone. A camera-based pulse can differ from a chest strap, a pulse oximeter, or the pulse number your cuff displays. Treat it as a useful approximation, not as a clinical value, and never as the basis for a decision about medication or treatment.

It is not an ECG. The app does not record an electrocardiogram, has no electrodes, and produces nothing that resembles one. Any waveform shown on screen or in the app icon is a stylised pulse trace, not an ECG trace.

It does not detect atrial fibrillation, arrhythmia, or any irregular heart rhythm, and it will never tell you that your rhythm is abnormal. When the app cannot get a steady signal it says exactly that and asks you to try again — a statement about the recording, never a statement about your heart. If you are worried about palpitations, a racing or skipping heartbeat, or any change in how your heart feels, that is a conversation with a clinician and no app is a substitute for it.

It produces no scores and no verdicts. There is no stress index, no recovery or readiness score, no energy level, no biological age, and no adjective attached to your number. The app shows what it measured, with units, and stops there. Only blood pressure gets reference colours in the app, because only blood pressure has a published reference table to present.

When the signal is not good enough, you get no number. The app applies quality thresholds and reports nothing at all rather than a plausible wrong value. A measurement that ends in "try again" is the app working correctly, not failing.

Using it safely. Measure while sitting or resting with your hand supported. Do not measure while driving, cycling, or operating machinery. The camera light stays on continuously for the length of the measurement — it does not flash or strobe — and the phone may become noticeably warm; if it becomes uncomfortable, stop. Press gently: pressing hard restricts blood flow at the fingertip and makes the measurement worse rather than better. The measurement is intended for adults measuring themselves, and it is not intended for children, for infants, or for monitoring anyone whose condition requires medical-grade equipment.

Do not use it in an emergency. If you feel faint, breathless, have chest pain, or otherwise think something is seriously wrong, get medical help. Do not spend two minutes measuring first.

Not a medical device

Tonelva is a record-keeping and general wellness application. It is not a medical device and has not been assessed, certified, cleared or approved as one anywhere. In the European Union it does not carry a CE mark and is not placed on the market as a medical device under Regulation (EU) 2017/745; in the United Kingdom it is not a UKCA-marked medical device; in the United States it is a general wellness product and has not been cleared or approved by the Food and Drug Administration. It is not intended to diagnose, treat, cure, mitigate or prevent any disease or condition, and it must not be used as a substitute for professional medical assessment, monitoring or advice.

When to seek urgent care

This is the one place where we will be directive. A very high reading together with chest pain, breathlessness, weakness or numbness, difficulty speaking, vision change, severe headache or confusion means emergency medical care, immediately. Do not enter it in a diary and wait. If you are unsure whether something is urgent, treat it as urgent and let a clinician decide.

Free tools on this site

The tools are provided free and without warranty of any kind. Everything you type stays in your browser and is never transmitted to us. Category thresholds are taken from the published guidelines and the formulas are printed on the pages so you can check any result by hand. If something looks wrong, it may be, and we would like to hear about it.

Your records

Readings and pulse measurements are stored on your device and nowhere else. We hold no copy, which means we cannot restore your history if you delete the app, lose the device, or reset it without a backup. Keeping a backup is your responsibility: use the export function, or enable Apple Health sync, which in practice becomes your recovery path.

What is free and what is paid

Logging readings, keeping unlimited history, both reference scales, and the thirty-second pulse measurement with its full unlimited history are free, and stay free. A Pro subscription adds the PDF report for your doctor, medication reminders, longer trend windows, CSV export, and the two-minute measurement with heart rate variability. We do not move a feature that was free in a published version behind the paywall afterwards; new capability may be paid, but what you already have does not become chargeable.

If a subscription lapses, nothing is deleted. Variability measurements you recorded remain on your device and become visible again if you resubscribe; your readings, your free pulse history and every export you already made are unaffected.

Subscriptions and billing

A Pro subscription costs $4.99 weekly or $39.99 yearly with a 7-day free trial on the yearly plan, where the store offers you one. Prices displayed in the app are taken from App Store Connect and Google Play Console and are authoritative; prices on this website are informational and may lag a change or differ by region and currency.

Subscriptions are sold and processed by Apple or Google, not by us. Payment is charged to your store account at confirmation of purchase. A subscription renews automatically for the same period at the same price unless auto-renew is turned off at least 24 hours before the end of the current period, and your account is charged for renewal within 24 hours before the period ends. If a free trial is offered and you subscribe to the same plan before it ends, the unused portion of the trial is forfeited, which is the store's rule rather than ours. You can manage the subscription and turn off auto-renewal in your Apple or Google account settings after purchase.

If a price changes, the store notifies you and, where the store's rules require it, asks for your consent before charging the new price; where consent is required and not given, the subscription does not renew.

Cancelling

Cancel at any time in your Apple or Google account settings. Cancelling during a free trial costs nothing as long as you cancel at least 24 hours before it ends. Cancellation takes effect at the end of the current billing period and you keep Pro features until then. We cannot cancel on your behalf because we do not control the billing relationship. Step-by-step instructions for both platforms are on the contact page.

Refunds and withdrawal rights

Refunds are handled by Apple and Google under their own policies and requests go through them. If you were charged in error, contact us as well — we cannot move the money, but we can support your request, and we will.

If you are a consumer in the European Union or the United Kingdom you may have a statutory right to withdraw from a purchase of digital content within fourteen days. That right can be lost once supply of the content begins with your consent, which is what happens when a subscription unlocks immediately. In practice the store's own refund process is the route that works, and neither these terms nor the store's policy removes any right you have under the mandatory consumer law of your country.

Acceptable use

Use the app and the site for their intended purpose. Do not attempt to disrupt them, do not reverse engineer, decompile or modify the app except to the extent that applicable law expressly permits, do not scrape the site at a volume that degrades it for others, and do not redistribute the calculators as your own product. Do not use the app or its output to provide a clinical service to other people. You may quote and link to anything we publish, and we would prefer that to an inaccurate paraphrase.

Intellectual property and licence

The app, the site design, the written articles and the calculators are our intellectual property. We grant you a personal, non-exclusive, non-transferable, revocable licence to use the app on devices you own or control, for your own non-commercial use, in accordance with these terms and with the usage rules of the store you installed it from. No other rights are granted.

Third-party names and trademarks appearing on this site, including the names of other apps on the comparison pages and the generic and brand names of medicines referred to descriptively, belong to their respective owners. Their appearance does not imply affiliation with or endorsement by those owners, and nothing here should be read as a claim to be associated with any pharmaceutical manufacturer or device maker.

Accuracy and corrections

We aim to be accurate and we will sometimes be wrong. Guidelines are also revised, and a threshold that is current today may not be in three years. If you find an error, or a page that has fallen behind a guideline update, write to [email protected]. We correct mistakes and we say that we have rather than editing silently. In a subject where an arithmetic error can matter, this is not a courtesy but a duty.

Feedback

If you send a suggestion or a feature idea, we may act on it without owing compensation or attribution. That exists because good ideas frequently arrive from several users independently and we cannot run a product where implementing an obvious improvement creates a claim. If you want to send something you consider confidential, tell us before you send it.

Availability and changes to the service

We may change, suspend or discontinue any part of the app or the site, including individual features and individual free calculators, and a feature may be unavailable on a device whose hardware cannot support it — the pulse measurement, for example, is hidden on devices without a rear camera and light rather than offered in a form that cannot work. We have no plan to remove any of the free calculators and we will not put an existing free one behind a paywall. If a paid feature were discontinued during a subscription period we would say so in the app, and the store's refund process remains open to you.

Third-party services

The app and site depend on services we do not control, including Apple and Google for distribution and billing and the providers named in the privacy policy. Their terms apply to their services. We are not responsible for the content or practices of any third-party site we link to.

Disclaimer of warranties

To the fullest extent permitted by law, the app, the site and the tools are provided as they are and as they are available, without warranty of any kind, whether express or implied, including any implied warranty of merchantability, fitness for a particular purpose, accuracy or non-infringement. We do not warrant that the app will be uninterrupted or error-free, that any measurement will be accurate for you on your device, or that the reference material reflects the most recent revision of every guideline. If you are a consumer, this clause does not affect the statutory rights that your local law gives you and that cannot be excluded.

Limitation of liability

To the fullest extent permitted by law, we are not liable for indirect or consequential loss arising from use of the app or the site, including any loss arising from reliance on a classification, an average, a pulse or a variability figure, from data lost when an app is deleted, or from any decision made about your health. Decisions about your treatment belong with your clinician, and this app is a record rather than an adviser. Where liability cannot be excluded, it is limited to the amount you have paid us in the twelve months before the claim, which for most users is zero. Nothing here limits liability for death or personal injury caused by our negligence, or for fraud, where such limitation is not permitted by law.

Severability, waiver and assignment

If a provision is unenforceable it is limited or removed to the minimum extent necessary and the rest stands. Not enforcing a provision once is not a waiver of it. You may not transfer your rights without our consent; we may assign ours as part of a merger, acquisition or sale of assets, on notice. With the privacy policy, these terms are the entire agreement between us about the app and the site.

Termination

Stop using the app at any time by deleting it. We may suspend access if the acceptable-use terms are breached in a way that harms the service or other users. Ending your use does not entitle you to a refund of a period already paid for, which remains subject to the store's policy.

Age

The app is intended for adults keeping their own record, or keeping one for a family member with their knowledge. You must be old enough to form a binding contract where you live in order to subscribe, and where you are under the age of majority a parent or guardian must agree to these terms on your behalf. The reference categories used throughout are adult thresholds and do not apply to children.

Export and portability

The app can export your record as a PDF or a CSV file that you keep, including a separate export of your pulse measurements. That export, and Apple Health sync if you enable it, are the only routes by which your data leaves the device, and both happen under your control rather than ours. Use one before changing devices, because we hold no copy and cannot restore anything.

If you installed from the App Store

These terms are between you and us alone. Apple is not a party to them. The following apply to any copy of the app obtained from the Apple App Store, and where they conflict with anything above, they prevail for that copy.

• Your licence to use the app is a non-transferable licence to use it on any Apple-branded device that you own or control, as permitted by the Usage Rules in the Apple Media Services Terms of Use, and on devices your family members may access under Family Sharing or volume purchasing where applicable.
• We alone are responsible for the app and its content. Apple has no obligation to provide any maintenance or support for it; support requests go to [email protected].
• If the app fails to conform to any applicable warranty, you may notify Apple, and Apple may refund the purchase price you paid for it. To the maximum extent permitted by law, Apple has no other warranty obligation whatsoever with respect to the app, and any other claims, losses, liabilities, damages, costs or expenses attributable to a failure to conform to a warranty are our responsibility.
• We, not Apple, are responsible for addressing any claim by you or a third party relating to the app or your use of it, including product liability claims, any claim that the app fails to conform to a legal or regulatory requirement, and claims arising under consumer protection, privacy or similar legislation, including in connection with the app's use of HealthKit.
• If a third party claims that the app infringes their intellectual property rights, we, not Apple, are solely responsible for the investigation, defence, settlement and discharge of that claim.
• You represent that you are not located in a country subject to a United States Government embargo or designated as a terrorist-supporting country, and that you are not listed on any United States Government list of prohibited or restricted parties.
• Apple and its subsidiaries are third-party beneficiaries of these terms, and upon your acceptance of them Apple has the right, and is deemed to have accepted the right, to enforce them against you as a third-party beneficiary.
• Our contact details for any question about the app are given at the end of these terms.

If you installed from Google Play

These terms are between you and us alone. Google is not a party to them and is not responsible for the app. Your use of Google Play is governed by the Google Play Terms of Service, and purchases made through Google Play are processed by Google under those terms. Where Google Play's terms give you a right that these terms do not, that right stands.

Governing law

These terms are governed by the laws of the Republic of Kazakhstan, where Vast Flow, LLP is established. If you are a consumer, this does not deprive you of the protection of the mandatory consumer law of your country of residence, nor of the right to bring proceedings in the courts of that country where your local law gives you that right.

Changes to these terms

We may update these terms as the app changes. The date at the top changes with them, and a material change is announced in the app rather than made quietly. Continuing to use the app after a change means you accept the updated terms; if you do not accept them, stop using the app and, if you have a subscription, cancel it in your store account.

Contact

Anything about these terms goes to [email protected], or by post to Vast Flow, LLP, Kunaeva 43, office 303, Almaty, Kazakhstan.