Callie - All in One Calculator

Everyday math, beautifully organized: calculator, currency conversion, money tools, unit conversion, percentages, and date math in one native 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.