Callie makes everyday math simple, fast, and satisfying. Switch between a classic calculator, a full scientific calculator, a built-in unit converter, and quick calculators for tip, discount, dates, fuel, loan payments and more.
It’s privacy-first, works fully offline, follows your device language, and is available internationally in 13 languages—with macOS support in progress.
Callie supports 13 languages and works offline. It’s designed for everyone—students, shoppers, cooks, builders, travelers, freelancers… anyone who needs quick, reliable math.
Callie’s classic calculator keeps everyday math fast and frictionless. Large, high-contrast keys, a clear display, and one-tap access to memory keys and history make it feel instantly familiar.
Behind the clean look is dependable power: type naturally, reuse past results, and carry running totals between calculations.
Pick a category—Length, Weight, Volume, Temperature, or Speed—and jump straight into a focused converter.
Choose units, enter a value, and see the answer immediately. No clutter, no hidden steps.
One-tap mini calculators for everyday tasks: Tip, Bill Split, Fuel Cost, Loan Payment, Sales Tax + Discount, Unit Price, Percent Calc, Date Calculator, and more.
Smart defaults and instant results so you finish in seconds.
Tap a percent, adjust the split, and Callie shows the totals instantly.
Perfect for dining out or quick counters. Reset anytime for a fresh start.
See real price instantly. Enter discount %, tax %, and list price to get the out-the-door total.
Great for shopping, budgeting, and checkout comparisons.
Count days between dates or project forward from today.
Ideal for scheduling, planning, or estimating timelines.
Switch between miles, km, feet, meters, and more without hunting through dense lists.
Simple, roomy layout keeps conversions fast and obvious.
From teaspoons to liters to gallons—Callie handles kitchen and lab volumes with ease.
Clean formatting and big numbers make it easy to double-check.
