The short version
HydraCal is free, provided as-is, and is a record-keeping tool rather than medical advice. Your data stays on your device, so keeping a backup is up to you. We are not connected to the makers of any nutritional product the app supports.
1. These terms
These terms govern your use of the HydraCal mobile app, published by Defender Days Ltd ("we", "us"), a company registered in England and Wales. By downloading or using the app you accept them. If you do not accept them, please do not use the app.
They should be read alongside our Privacy Policy and our Medical Disclaimer. The Medical Disclaimer matters most, and we would rather you read that one than this one.
2. Not medical advice
HydraCal records what you enter and shows you totals. It is not a medical device, does not provide medical, dietary or clinical advice, and is not intended to diagnose, treat, cure or prevent any disease. The targets built into the app are placeholder defaults, not recommendations.
Always follow the plan given to you by your dietitian, nurse or doctor, and contact them if you are unwell or struggling with your intake. Full details are in the Medical Disclaimer, which forms part of these terms.
3. Licence to use the app
HydraCal is provided free of charge. We grant you a personal, non-exclusive, non-transferable, revocable licence to use it on devices you own or control, for your own personal or family use, in line with the App Store Terms of Service.
You may not sell, rent, sub-licence or redistribute the app; copy or modify it, or attempt to derive its source code, except to the extent that applicable law expressly permits; remove any copyright or ownership notices; or use it unlawfully or in a way that harms others.
4. Your data and your backups
Everything you record is stored on your own device and nowhere else. We hold no copy. That is a deliberate privacy decision, and it has one practical consequence you should understand:
- If you lose, reset, wipe or replace your device, or delete the app, your HydraCal history goes with it, and we cannot recover it for you.
- If your records matter to you — for example because you are sharing them with your clinical team — use the app's backup and export features, and keep those files somewhere safe.
5. Availability and changes
We may update, change or withdraw the app at any time, and we may stop supporting it altogether. It is offered as a personal project rather than a commercial service, and we do not promise continued availability, updates, or compatibility with future versions of iOS. If we do withdraw it, your existing data stays on your device and your export and backup options continue to work.
6. No warranty
HydraCal is provided "as is" and "as available", without warranties of any kind, whether express or implied, to the fullest extent permitted by law. In particular we do not warrant that the app will be uninterrupted or error-free, that any defect will be corrected, that its calculations or the nutritional values it uses are accurate or current, or that it is fit for any particular purpose including any clinical or nutritional one.
Manufacturers reformulate products and change pack sizes. Always check the packaging of what you are actually using.
7. Our liability
Nothing in these terms limits or excludes our liability for death or personal injury caused by our negligence, for fraud or fraudulent misrepresentation, or for anything else that cannot lawfully be limited or excluded.
Subject to that, and to the fullest extent permitted by law, we are not liable for any loss or damage arising from your use of, or inability to use, the app — including loss of data, loss of records, or any decision taken on the basis of information the app displayed. HydraCal is a diary; the clinical decisions remain yours and your healthcare team's.
If you are a consumer, you have legal rights that these terms do not affect.
8. Trade marks and third parties
Fortisip® and Calogen® are registered trade marks of Nutricia / Danone. Vital® is a registered trade mark of Abbott Laboratories. All other product names and marks belong to their respective owners.
HydraCal is an independent app and is not affiliated with, endorsed by, sponsored by or connected to Nutricia, Danone, Abbott, the NHS, or any other manufacturer, healthcare provider or charity. Product names appear in the app solely so that you can identify what you are recording.
"HydraCal" and "Defender Days" are marks of Defender Days Ltd.
9. Feedback
If you send us suggestions, we may act on them without obligation, payment or attribution. Please do not send us personal health information or identifying details in feedback — we do not need them and would rather not hold them.
10. Changes to these terms
We may revise these terms from time to time. The current version will always be at this address, with the date at the top updated. Continuing to use the app after a change means you accept the revised terms.
11. Governing law
These terms are governed by the law of England and Wales, and the courts of England and Wales have exclusive jurisdiction. If you are a consumer resident elsewhere in the United Kingdom, you may bring proceedings in your own jurisdiction.
12. Contact
Please use the contact form.