Online calculators

BMI Calculator Calculate your body mass index and see the WHO classification and healthy weight range. Rule of three (proportion) calculator Solve simple and compound proportions, including direct and inverse proportions, with the formula. Compound Interest Calculator Estimate investment growth with monthly contributions, a monthly or annual rate, and a month-by-month table you can download as a CSV. Percentage Calculator Find X% of Y, calculate increases, discounts, and percentage changes. Time Calculator Add and subtract hours and minutes, find the time between two times (including across midnight), and calculate your time balance. Pregnancy Calculator Find your estimated due date, how many weeks pregnant you are, and the milestones for each trimester. Fertile Window Calculator Estimate ovulation and your fertile window for the next 3 cycles based on your last period and cycle length. Square Footage Calculator Calculate room areas, how many flooring boxes to buy with extra for waste, and how many gallons of paint you'll need. Date Difference Calculator Calculate the number of days, weeks, months, and years between two dates, or add days to a date. Age Calculator Find your exact age in years, months, and days, and see how many days until your next birthday. Discount Calculator Find the sale price, see how much you’ll save, and calculate the real discount on a deal. Grade Calculator Calculate your simple or weighted average and find out what grade you need to pass. Calorie Calculator Find out how many calories you burn each day (BMR and total daily energy expenditure) and your calorie goal for maintaining, losing, or gaining weight. Daily Water Intake Calculator Find out how many liters of water to drink each day based on your weight, with adjustments for exercise and hot weather. Running Pace Calculator Calculate your running pace (min/km), race time, or distance, and see predicted times for the 5K, 10K, half marathon, and marathon. Markup and Selling Price Calculator Calculate your selling price using markup, taxes, fees, fixed expenses, and your desired profit. Check the profit on your current price, too. World Clock See the current time in multiple cities side by side, along with the time difference from your location. Add or remove cities—the list stays saved on your device. Time Zone Converter Convert a time from one city to another and find a meeting time that works for everyone. Time zone difference See the time difference between two places today and throughout the year, including when daylight saving time changes the offset.