Find what % of a number is, calculate % increase/decrease, or find the original number before a % change.
X% of Y = ?Enter original price and discount % to get the final price and total savings instantly.
Final = Price ร (1 - Discount%)Calculate simple or compound interest. Input principal, rate, and time to get total interest earned or owed.
A = P(1 + r/n)^(nt)Calculate Body Mass Index from height and weight. Supports metric (kg/cm) and imperial (lb/ft) inputs.
BMI = weight(kg) / height(m)ยฒCalculate exact age in years, months, and days from a birth date. Also finds the day of the week you were born.
Today โ BirthdateEnter your bill amount and tip % to get the tip amount, total bill, and split per person for groups.
Tip = Bill ร Tip% / PeopleCalculate area and perimeter for circle, square, rectangle, triangle, and other common shapes.
Circle: A = ฯrยฒEstimate your electricity bill by entering appliance wattage, hours of use, and your kWh rate.
Cost = W ร H ร Rate / 1000Choose the type of calculator you need from the menu โ Percentage, Discount, Interest, BMI, Age, Tip, Area, and many more.
Fill in the required input fields. Each calculator shows clearly labeled inputs with example values so you always know what to enter.
Hit the Calculate button. The result appears instantly with a clear breakdown showing the formula used and each step of the calculation.
Results are displayed in plain language. Copy the result, or use the "Show Work" option to see the full calculation steps for reference or learning.
To find 15% of any number, find 10% (move decimal left) then add half of that. Example: 15% of 80 = 8 + 4 = 12. Use the tool to verify instantly.
Simple interest grows linearly. Compound interest grows exponentially. For long-term savings, always use compound interest to see the real power of investing early.
BMI is a rough population-level screening tool, not a perfect health indicator. It doesn't account for muscle mass, bone density, or body fat distribution. Use it as one data point, not a diagnosis.
US restaurant tips: 15% (satisfactory), 18% (good), 20%+ (excellent). In many other countries, tipping is optional or culturally different โ check local norms when traveling.