Flex Calculators vs Twin Calc

Flex Calculators is a powerful all-in-one calculator app built for everyday problems and advanced math. Use it as your daily calculator, then switch to specialized tools for equations, calculus, statistics, finance, time, and conversions. Key features: - Scientific calculator - Fast expression input and real-time result preview - History support for quick reuse - Configurable angle mode (degrees/radians) - Real-only or complex result handling - Advanced math tools - Equation solver - System of equations and system of inequalities - Matrix calculator - Vector calculator - Derivatives and integrals - Statistics and distributions - Value table and proportion tools - Number base converter - Unit converter - Convert across many categories including: length, mass, area, volume, temperature, time, speed, force, pressure, energy, power, electrical, light, sound, data, performance, chemistry, and biology - Daily life calculators - Currency converter - Energy/fuel cost calculator - BMI/body index calculator - Loan payment calculator - Savings calculator - Date calculator - World hour/time-zone tool - Personalization and display controls - Light, dark, or system theme - Custom theme color - Multi-language interface - Decimal precision setting - Number formatting options (including thousand separators) - Ads and purchase - Banner/interstitial ads may be shown - One-time purchase option to remove ads Why users choose Flex Calculators: - One app for both basic and advanced calculations - Clean workflow for study, engineering, and daily finance tasks - Practical tools that reduce the need to install multiple calculator apps Whether you need quick arithmetic, equation solving, conversions, or planning daily expenses, Flex Calculators helps you solve it faster.

Twin Calc puts two independent calculators on one screen — a simple calculator app for anyone who has ever wished they had two. Compare two estimates. Split a bill two different ways. Convert on one side while you total on the other. Check last year's numbers against this year's. Open Twin Calc and calculators A and B are already there — no onboarding, no sign-up. Features - Calculator A and B stacked vertically (or side by side in landscape), each fully independent - Works just like the built-in iPhone calculator: + − × ÷, %, ±, backspace, and thousands separators - An expression line shows what you are calculating, so you never lose track - Drag the divider to resize the two calculators; double-tap to reset to half and half - Long-press a result to copy it; swipe left to delete one character - Haptic feedback (can be turned off) - History (tape) keeps your results automatically — tap to copy, or send a result back to A or B - Light and dark themes that follow your system setting - Both calculators and the split ratio are restored exactly as you left them Free - Two calculators, history, and reuse of your 3 most recent results - No ads PRO (one-time purchase) - Never retype a result again: send A's answer straight to B, or swap A and B in one tap - Bring back any past result from history - 3 extra themes: Midnight, Paper, and Mono PRO is a single one-time purchase. No subscription, no extra fees. Everything you calculate stays on your device and is never sent to a server. For iPhone (portrait and landscape).