About this app
Callie is an all-in-one calculator and everyday utility workspace for iPhone and iPad. Built for the small calculations that come up all day, Callie brings together a clean calculator, practical money tools, unit conversion, currency conversion, percentage math, and date tools in one focused native app. Whether you are splitting dinner, checking a sale price, converting measurements, comparing unit prices, counting days, or switching into scientific mode, Callie keeps the workflow fast, readable, and calm. MONEY & EVERYDAY COSTS Handle the money math that usually makes you pause. Callie includes tools for: • Tip Calculator • Bill Split • Sales Tax & Discount • Unit Price • Fuel Cost • Loan Payment • Currency Converter Quickly calculate tips, split totals between people, estimate sales tax and discounts, compare package value by unit, estimate trip fuel costs, or run a simple loan payment estimate. The Currency Converter uses public Frankfurter exchange-rate data, with searchable currencies, common currency shortcuts, favorites, recent selections, and local caching after your first successful update. CALCULATOR Use Callie as your daily calculator, then switch into Scientific mode when you need more. Basic mode is built for fast everyday arithmetic with clear input, memory controls, percent, sign toggle, backspace, and standard operations. Scientific mode adds support for trigonometry, logarithms, exponents, square root, square, reciprocal, π, e, and memory keys for multi-step calculations. UNIT CONVERSION Convert common measurements without digging through menus. Callie includes unit conversion for: • Length • Weight • Volume • Temperature Switch between common units like feet, inches, meters, miles, grams, pounds, liters, gallons, Celsius, Fahrenheit, Kelvin, and more. PERCENTAGE HELPER Solve everyday percentage questions faster. Use dedicated modes for: • What is X% of Y? • What percent? • Change by percent Great for discounts, comparisons, price changes, quick checks, and everyday math. DATE TOOLS Work with dates in a clear, simple workspace. Callie can calculate the difference between dates, add days or offsets, and compare ages or date spans. See total days and readable year/month/day differences without opening another app. PRIVATE BY DESIGN Callie does not require an account or sign-in. Calculator, money, unit, percentage, and date tools run on your device. Currency conversion uses public exchange-rate requests. Free users may see non-personalized banner ads, and a one-time Remove Ads purchase is available. BUILT FOR IPHONE & IPAD Callie is native on iPhone and iPad, localized for 32+ languages, and designed around a dark glass interface that keeps everything calm, readable, and organized. One app. Fast answers. Everyday math, beautifully organized.
Latest release
What’s New
Callie 2.1 makes everyday calculation faster and more personal. • A redesigned expression calculator with conventional percentages, repeat equals, persistent memory, history, and keyboard support • A new Algebra (CAS) workspace for simplifying, expanding, factoring, solving, differentiating, and integrating supported expressions • Floating liquid-glass calculator controls and four themes with custom colors • A purpose-built iPad calculator layout • Improved ad-banner clearance, localization, accessibility, and stability
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Aug 23, 2026 · 6:09 AM Free
Screenshots
