calculator DUO vs CodeHouse

A scientific calculator with history, memory and a keypad made for one hand. Save useful answers and tap to use them again on iPhone and iPad. WITHIN THUMB REACH Move and resize the left- or right-hand keypad to suit your grip. KEEP THE ANSWERS YOU NEED Save useful results on a visual shelf. Tap to reuse them, recall your last answer, or search your calculation history and mark favorites. CORRECT INPUT WITH CONFIDENCE Swipe to delete a digit or function. The deleted content stays visible until your next input; tap the return button to undo the deletion. FROM EVERYDAY TO SCIENTIFIC Use arithmetic, percentages, powers, roots, logarithms and trigonometric functions. Long-press a result for a large display, with adjustable text, color, font and size. MAKE IT YOURS Five themes, optional digit grouping and an interface in 50 languages. No account is required. Expressions, saved results and calculation history are stored on your device. DATES AND TIME, TOO Find the time between two dates, add or subtract days and hours, and calculate across time zones. The free app may show banner ads. Remove Ads is an optional one-time purchase, with purchase restoration through the same Apple Account.

CodeHouse is an offline encrypted vault secured by FIDO2 hardware security keys (YubiKey). SECURITY FIRST • Hardware-grade encryption: private keys never leave your security key; all cryptographic operations happen inside the key's secure chip • Fully offline: no accounts, no cloud — your data stays on your device • No backdoors: without your key, the vault cannot be opened — not even by us. That is the point • Layered protection: vault PIN + key FIDO PIN + physical touch, all required • Brute-force proof: the key's chip enforces a hardware PIN retry counter and locks itself FILE MANAGEMENT • Encrypt any file: documents, photos, videos, audio • Folder hierarchy with multi-select, batch move and batch delete • Global search: find any file across the entire vault instantly, with full paths • In-app preview: TXT/Markdown editing, PDF and Office preview, audio/video playback, image viewing • One-tap import from your photo library MULTI-KEY & CROSS-PLATFORM • Authorize multiple security keys, each with its own PIN — perfect for backups or family members • Clear key list showing type, authorization time, and source device • Vault files work seamlessly across iPhone, iPad, and Mac FREE & PRO • Free: full encryption, one vault (CodeHouse.vault) • Pro (one-time purchase): unlimited vaults, custom names, multi-key authorization, and everything else PRIVACY PROMISE CodeHouse collects nothing. No analytics, no ads, no tracking. Your files and keys belong to you alone. Note: keep your security keys and PINs safe. With a no-backdoor design, data cannot be recovered if all authorized keys are lost.