Smart Calculator

Percentage, tip, age, time diff & BMI calculators in one place.

Percentage Calculator

Percent of, what percent, percent change

About Smart Calculator

All-in-one calculator suite with 5 specialized calculators: Percentage Calculator, Tip & Bill Splitter, Age Calculator, Time Difference Calculator, and BMI Calculator. Fast, accurate, and easy to use — no app required.

How to Use

  1. 1Select the calculator type from the tab strip at the top.
  2. 2Fill in the required fields for that calculator.
  3. 3Click "Calculate" (or see live results for tip/BMI).
  4. 4Results appear instantly below the inputs.

Frequently Asked Questions

What calculators are included?
Smart Calculator includes: Percentage (X% of Y, what percent, percent change), Tip & Bill Splitter, Age Calculator with zodiac sign, Time Difference, and BMI with healthy weight range.
How does the Tip Calculator work?
Enter your bill amount, select a tip percentage (or enter a custom one), and optionally split between multiple people. The calculator shows tip amount, total, and per-person breakdown.
How accurate is the Age Calculator?
The Age Calculator computes your exact age in years, months, and days, plus total days lived, weeks, and a countdown to your next birthday.
Which BMI units are supported?
Both Metric (cm/kg) and Imperial (ft+in / lbs) are supported. The tool also shows your healthy weight range for your height.