Privacy policy

1. Who is responsible

The app is published by, and the controller for the purposes of the EU General Data Protection Regulation (GDPR) is:

Privacy questions and requests: privacy@sigmastone.io.

In this policy "we" means Sigmastone OÜ and "the app" means Compound Interest Calculator.

2. What the app stores on your device

The app works without an account and without a connection to any Sigmastone server. It keeps the following on your device only:

• the numbers you last entered in the calculator, so that the app reopens where you left it;
• the scenarios you save, with the names you give them;
• your settings, such as the display currency and the theme;
• your advertising consent choices, stored by Google's consent software (see section 3).

None of this is sent to us. We cannot see it, and we have no copy of it.

Your device's own backup service may include the app's data in a backup of your device if you have switched that on: Google's backup on Android, and Apple's iCloud backup on iOS. Those backups are made under your agreement with Google or Apple and are not available to us.

You can delete this data at any time by clearing the app's storage in your device settings or by uninstalling the app. Single scenarios can be deleted inside the app.

The historical market and inflation data used by the calculator is part of the app. The app does not download it and does not send your calculations anywhere.

3. Advertising through Google AdMob

The app is free and shows banner advertisements. The advertisements are delivered by Google AdMob, a service of:

• Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland, if you live in the European Economic Area or Switzerland;
• Google LLC, 1600 Amphitheatre Parkway, Mountain View, CA 94043, USA, if you live anywhere else.

To deliver advertisements, the app contains Google's advertising software (the Google Mobile Ads SDK) and Google's consent software (the User Messaging Platform). When the app requests an advertisement, this software collects the following directly from your device and sends it to Google and, depending on your choices, to Google's advertising partners:

• Device and advertising identifiers. On Android, the advertising ID. On iOS, the identifier for vendors (IDFV), and the advertising identifier (IDFA) only if you have allowed tracking for the app.
• IP address, and the approximate location (country, region or city) that can be derived from it. The app does not ask for, and does not use, your device's precise location.
• Device and app information, such as the device model, operating system version, screen size, language, and the app's name and version.
• Advertisement interactions: which advertisements were shown in the app and whether they were tapped.
• Diagnostics: technical information about how the advertising software performs, such as loading times and errors.

The numbers you enter into the calculator, your results and your saved scenarios are not part of this and are not shared with Google or anyone else.

We do not receive the identifiers or the IP address ourselves. Google gives us only aggregated reports, for example how many advertisements were shown and tapped per day and per country, which do not identify any person.

Google decides, together with its advertising partners, how the data collected through its software is used for advertising, and is a controller of that data in its own right. We are responsible for the decision to include Google's software in the app and for obtaining your consent where the law requires it.

4. What the advertising data is used for

The data described in section 3 is used for:

• selecting and delivering advertisements in the app;
• limiting how often you see the same advertisement (frequency capping);
• measuring and reporting how advertisements perform;
• detecting and preventing fraud, abuse and security problems;
• and, only if you consent, showing personalised advertisements, that is advertisements chosen on the basis of a profile of your interests.

If you live in the European Economic Area, the United Kingdom or Switzerland, the consent form shown by the app follows the Transparency and Consent Framework of IAB Europe. It lists each purpose for which data may be used and each advertising technology provider that may receive data, and lets you accept or refuse them one by one. You can open that list again at any time under Settings, Privacy options.

If you do not consent to personalised advertisements, the app may still show advertisements that are not based on a profile of you, to the extent Google supports this.

We do not use your data for automated decisions that have legal or similarly significant effects on you.

5. Legal bases

Where the GDPR applies:

• Consent (Article 6(1)(a) GDPR, and the ePrivacy rules on storing and reading information on a device as they apply in Estonia) is the basis for storing information on your device and reading it for advertising, including the advertising identifier, and for personalised advertisements. The app requests no advertisement until Google's consent software reports that it may.
• Legitimate interests (Article 6(1)(f) GDPR) are relied on by Google and some advertising technology providers for certain purposes where the Transparency and Consent Framework permits it, for example measuring advertisement delivery and preventing fraud. Our own legitimate interest is to finance a free app through advertising. You have the right to object to processing based on legitimate interests; the consent form lets you do so for each purpose and provider.

The data that stays on your device (section 2) is stored only because the functions you use need it, and we do not process it.

6. Changing or withdrawing your consent

You can change or withdraw your advertising choices at any time. Withdrawing consent does not affect the lawfulness of processing before the withdrawal, and the calculator works the same whatever you choose.

• In the app: open Settings and choose Privacy options. This reopens the consent form. The entry is shown wherever a consent choice applies to you.
• On Android: in your device settings, under Privacy (or Google), Ads, you can reset or delete your advertising ID. Deleting it stops apps from using it for advertising.
• On iOS: in the device's Settings, under Privacy and Security, Tracking, you can control whether apps may ask to track you.

7. Google's own policies

Google describes how it uses the data it collects through its advertising software in:

• How Google uses information from sites or apps that use our services
• Google Privacy Policy

Apart from Google and the advertising technology providers listed in the consent form, we share no personal data with anyone, and we do not sell personal data for money.

8. Transfers outside the European Economic Area

Google and its advertising partners may process the data described in section 3 in countries outside the European Economic Area, including the United States. Google LLC is certified under the EU-US Data Privacy Framework, which the European Commission has recognised as providing adequate protection. Where a transfer is not covered by an adequacy decision, Google relies on the standard contractual clauses approved by the European Commission. Google's policies linked in section 7 describe this in more detail.

9. How long data is kept

• Data on your device (section 2) stays until you delete it, clear the app's storage or uninstall the app. We hold no copy, so there is nothing for us to delete.
• Your consent choices stay on your device until you change them, clear the app's storage or uninstall the app. The consent form is shown again when your choices expire or when the list of advertising providers changes.
• Advertising data held by Google is kept for the periods set out in Google's policies linked in section 7.
• Emails you send us are kept for as long as dealing with your request needs, and longer only where the law requires it.

10. Security

The data described in section 2 is kept in the app's private storage on your device, which other apps cannot read, and is protected by your device's own security, such as its screen lock and encryption. We operate no server that holds data from the app, so there is no copy elsewhere that could be lost or disclosed by us.

The data that Google's advertising software sends from your device (section 3) is encrypted in transit.

11. Your rights

Under the GDPR you have the right to:

• ask whether we process personal data about you, and receive a copy (access);
• have inaccurate data corrected (rectification);
• have data deleted (erasure);
• have processing restricted;
• object to processing that is based on legitimate interests;
• receive data you provided in a portable format (portability);
• withdraw a consent at any time (see section 6).

To use any of these rights, write to privacy@sigmastone.io. We answer within one month.

Please keep in mind that we hold no data from the app that identifies you: your inputs never leave your device, and the advertising identifiers go to Google, not to us. For the advertising data, we will tell you how to make your request to Google, and you can also contact Google directly using the policies linked in section 7.

You also have the right to lodge a complaint with a supervisory authority. Ours is the Estonian Data Protection Inspectorate (Andmekaitse Inspektsioon), Tatari 39, 10134 Tallinn, Estonia, info@aki.ee, www.aki.ee. You may instead complain to the authority of the country where you live or work.

12. Children

The app is intended for adults and is not directed at children. We do not knowingly collect personal data from children. If you believe a child has used the app and you have a concern about it, write to privacy@sigmastone.io.

13. Residents of US states

Some US states, including California, give their residents additional privacy rights. If you live in one of them:

• The categories of personal information collected through the app are the ones listed in section 3: identifiers, internet or network activity (advertisement interactions), and approximate location derived from the IP address. They are collected for the purposes listed in section 4.
• We do not sell personal information for money. However, letting Google's advertising software collect identifiers in order to show personalised advertisements may count as "selling" or "sharing" personal information, or as "targeted advertising", under some state laws.
• You can opt out of this. Where the app shows a Privacy options entry under Settings, use it to opt out of the sale or sharing of your personal information and of targeted advertising. In every case you can delete your advertising ID in your device settings (section 6), which stops apps from using it for advertising.
• You may ask to know, correct or delete personal information, and we will not discriminate against you for using these rights. Write to privacy@sigmastone.io. As explained in section 11, we ourselves hold no personal information from the app.
• The app is not directed at children, and we have no actual knowledge that we sell or share the personal information of anyone under 16.

14. This website and email

These pages set no cookies, run no scripts and load nothing from third parties. We keep no logs of who visits them. They are hosted on Amazon Web Services, which processes your IP address for the moment it takes to deliver a page to your browser.

If you write to us by email, we use your address and your message only to answer you. Our mail is processed by service providers acting on our behalf.

15. Changes to this policy

We will update this policy when the app or the law changes, for example if the app gains new features that involve personal data. The version and the date from which it applies are shown at the top of this page. If a change is significant, we will also point it out in the app or in the app's store listing. Earlier versions are available on request.