Bitcoin Gains Checker

BTC Gains Checker
Private overview of your BTC portfolio value over time.

Record your Bitcoin purchases and sales to track the growth and value of your portfolio — in real time, without compromising your privacy.

BTC Gains Checker stores your transaction data exclusively on your phone. No user account is required and no data is sent to a server. The app connects to the internet solely to retrieve the current BTC price.

The optional backup feature works by sending data encrypted with AES-256-GCM — using a key derived from your passcode — to Apple's servers. Only an unreadable encrypted file reaches Apple's servers, meaning neither the operator nor Apple can read your transactions.

FEATURES
Portfolio overview – BTC holdings, total fiat invested, portfolio value, average purchase price, current profit or loss, current BTC price.
Interactive chart – visualise your portfolio performance over time.
Landscape chart – rotate your phone to landscape for a larger chart view.
Historical P&L (Profit & Loss) – see how the fiat value of your BTC has developed over time based on actual historical BTC prices.
Transaction import & export – bulk transfer of transactions without manual entry.
Multi-currency support – USD, EUR or CZK with the ability to mix currencies across transactions.
Passcode & Biometrics – secure app access with a passcode and Face ID or fingerprint.
Data encryption – option to enable encryption of app data based on your passcode.
Encrypted iCloud backup – option to enable iCloud backup. Data can sync across your devices (same Apple ID and same passcode). Data is encrypted directly on your device. Without your passcode it is unreadable by anyone else.
Hide balances – press the button or place your phone face down to blur sensitive information, protecting your privacy.

PRIVACY & TECHNICAL APPROACH
Most portfolio trackers require account creation and store your financial data on their servers. BTC Gains Checker works in a completely private way. Your data is never visible to the operator or to Apple.
Transaction data is stored locally on your device.
No registration, no account, and no need to share data with a server.
The app connects to the internet only to retrieve the current and historical BTC price.
The app contains no analytics or advertising SDK. We collect only anonymous crash reports.
The passcode is used to unlock the app and to encrypt your data. Without the passcode, data cannot be decrypted.
The optional cloud backup and cross-device sync uses end-to-end AES-256-GCM encryption with a key derived from your passcode. All devices must share the same passcode for sync to work. Nobody but you can read the data on the server.