Callie - All in One Calculator

Callie is an all-in-one calculator, scientific calculator, unit converter, percentage calculator, money calculator, and date calculator for iPhone and iPad. Built for the math that comes up every day, Callie combines a clean everyday calculator with scientific tools, Algebra/CAS, tip and bill splitting, sales tax and discounts, loan payments, currency and unit conversion, percentages, date calculations, and more. No accounts. No clutter. Just useful tools and clear answers. CALCULATOR Use Callie as a fast everyday calculator, then switch to Scientific mode when you need more. Basic Calculator includes: • Standard arithmetic • Percent calculations • Positive/negative toggle • Memory controls • Backspace and clear • Calculation history • Live thousands separators Scientific Calculator includes: • sin, cos, tan • Logarithms • Exponents and powers • Square root • Reciprocal • π and e • Degree calculations • Memory controls Scientific mode is designed for a focused landscape workspace on iPhone and iPad. ALGEBRA & CAS Need more than a standard calculator? Callie includes an Algebra/CAS workspace for symbolic math, including: • Simplify expressions • Solve equations • Expand expressions • Factor expressions • Derivatives • Integrals Useful for algebra, coursework, quick symbolic checks, and everyday problem solving. MONEY CALCULATORS Handle common money math without opening a spreadsheet. Callie includes: • Tip Calculator • Bill Split Calculator • Sales Tax & Discount Calculator • Unit Price Calculator • Fuel Cost Calculator • Loan Payment Calculator • Currency Converter Calculate a restaurant tip, split a bill between friends, check a sale price, estimate tax, compare package prices, calculate fuel costs, or estimate monthly loan payments in seconds. CURRENCY CONVERTER Convert currencies using public Frankfurter exchange-rate data. Features include: • Searchable currencies • Common currency shortcuts • Favorites • Recent currencies • Locally cached rates after a successful update Perfect for travel, shopping, budgeting, or quick exchange-rate checks. UNIT CONVERTER Convert common measurements in one clean workspace. Supported categories include: • Length • Weight • Volume • Temperature Convert feet to inches, miles to kilometers, pounds to kilograms, gallons to liters, Celsius to Fahrenheit, and more. PERCENTAGE CALCULATOR Answer common percentage questions without remembering the formula. Dedicated modes include: • What is X% of Y? • What percent is X of Y? • Increase or decrease by a percentage Useful for discounts, markups, price changes, comparisons, taxes, tips, and everyday percentage math. DATE CALCULATOR Work with dates without counting days on a calendar. Callie can: • Calculate the difference between two dates • Show total days between dates • Show years, months, and days • Add days to a date • Compare ages and date spans Great for deadlines, travel planning, project timelines, anniversaries, age differences, and date math. MADE TO FIT YOUR STYLE Customize Callie to make it feel like yours. Choose from built-in appearance presets including: • Callie Cyan • Ocean • Solar • Violet PRIVATE BY DESIGN Callie does not require an account or sign-in. Most calculator, algebra, money, percentage, unit, and date tools run directly on your device. Currency conversion requires an internet connection to retrieve exchange-rate data. The free version may show occasional ads during some advanced-tool workflows. Basic calculator use remains uninterrupted. A one-time Remove Ads purchase removes advertising from Callie. BUILT FOR EVERYDAY USE Callie brings together the tools you would otherwise keep scattered across several apps: Calculator. Scientific calculator. Algebra. Tip calculator. Bill splitter. Sales tax. Discounts. Loan payments. Currency conversion. Unit conversion. Percentages. Dates. One app. Clear answers. Less in the way.