Summary: Metron does every conversion on your device and makes no network request of its own — there is no server to send anything to. Your history and favourites stay on your device; with Metron Pro they also sync through your own private iCloud, which only you can see. The free version shows ads served through Unity LevelPlay, which collects limited device and ad-interaction data to do so. Ads are non-personalised by default, everywhere in the world; a switch in Settings lets you opt in, and leaving it off costs you no features. Metron Pro removes ads entirely. There is no account and no sign-in.
Metron is developed by MW Supply Limited (“we”). This policy explains what stays on your device and what is processed by the limited third-party services we use to show ads in the free version and to offer an optional Pro upgrade. The app has no account system and no backend of any kind — every feature works without signing in to us, and most of them work with no network at all.
Metron stores the following on your device so the app remembers it between launches:
This stays on your device, is never sent to us, can be cleared at any time from History, and is removed entirely if you delete the app.
iCloud sync (Metron Pro). If you subscribe to Pro, your history and favourites are also synced through your own private iCloud database using Apple’s CloudKit, so they stay in sync across your devices and are restored when you set up a new one. This data lives in your personal iCloud account under your Apple ID — it is visible only to you, handled under Apple’s iCloud terms and privacy policy, and we never receive it or have access to it. Your history and favourites sync only with Pro. Your preferences — digits, notation, theme and the like — sync through Apple’s iCloud key-value store at every tier, including the free one, so the app looks the same on each of your devices; they are settings, not personal data, and they are equally invisible to us. You can stop all of it by turning iCloud off for Metron in iOS Settings › Apple Account › iCloud.
Metron contains no analytics SDK, no crash-reporting service other than Apple’s own first-party reporting, and no tracking framework. It does not access your location, camera, microphone, contacts, photos, or health data. It has no servers, so what you convert is not, and cannot be, sent to us.
The free version of Metron is supported by ads served through Unity LevelPlay (ironSource), a mediation service that runs an auction between advertising networks. There are three places an ad can appear:
No ad ever appears in the results list, in the unit list, on the paywall, or on the membership page. There are no ads in the widgets, in Shortcuts, or anywhere outside the app itself.
To serve these, our advertising partner may collect and process information including:
This information is collected and used by Unity, not by us, under Unity’s Player and App User Privacy Policy. MW Supply Limited receives only aggregate, non-identifying reports such as ad impressions and estimated revenue. What you convert is never shared with any advertiser or used to target an ad.
Personalised ads are off by default, for everyone. Metron reports “no consent on record” to its advertising partner unless you turn the Personalised ads switch on yourself in Settings. That is not limited to the EEA, the UK and Switzerland — it is how the app behaves everywhere. Turning the switch off is not an off switch for advertising: you still see ads, they are simply generic rather than personalised, and you keep every feature either way.
App Tracking Transparency. iOS asks whether Metron may track you across other companies’ apps and websites. If you choose “Ask App Not to Track,” the advertising identifier is not used. The app works fully either way, and no feature, content or reward depends on your answer.
Removing ads. Upgrading to Metron Pro removes all three ad formats entirely. While you hold Pro the app does not even start the advertising SDK, let alone request or display an ad.
Metron Pro removes all ads and adds the expression solver, significant figures and uncertainty propagation, the CODATA constants library inside calculations, molar mass from a chemical formula, unlimited history and favourites, export to CSV, LaTeX and Markdown, and iCloud sync. It is available as an auto-renewable subscription (monthly or annual) or as a one-time Lifetime purchase that never renews.
Purchases, billing, renewals and refunds are handled entirely by Apple through the App Store using StoreKit — we never see or store your name, your card number, or your Apple Account. To unlock Pro, the app checks your purchase entitlement directly with the App Store on your device; that check does not identify you to us. Manage or cancel anytime in iOS Settings › Apple Account › Subscriptions, or from the Membership page inside the app.
Apart from the advertising and purchase services described above — and, for Pro subscribers, syncing to your own private iCloud as described in section 2 — Metron makes no network requests of its own. Every conversion, every constant and every calculation is computed on your device from data shipped inside the app. The app works completely offline.
To show ads in the free version, Metron includes the Unity LevelPlay (ironSource) mediation SDK and the Unity Ads adapter it auctions through. These are governed by Unity’s Player and App User Privacy Policy. Metron Pro members are not shown ads and the app does not request ads for them.
Metron is a general-audience reference tool rated 4+ on the App Store, and is declared to our advertising partner as not directed to children. Because the free version shows ads, we use the ad-quality controls our partner provides: served creatives are screened for adult, gambling, alcohol, drug and dating content, and flagged advertisers are blocked across our apps. We do not knowingly collect personal information from children. Upgrading to Metron Pro removes all ads.
Because we hold no personal data about you, there is nothing for us to export, correct or delete. Data stored on your device is removed when you delete the app; data in your private iCloud database is under your control in iOS Settings › Apple Account › iCloud. To withdraw consent for personalised advertising, turn off Personalised ads in Metron’s Settings, and revoke tracking permission in iOS Settings › Privacy & Security › Tracking.
If we change how Metron handles data, we will update this page and the “Last updated” date above. Material changes will also be reflected in the App Store privacy labels for the affected version.
Questions about this privacy policy can be sent to mwsupplylimited@gmail.com.