Free online calculators

Work out what a given percentage of a number is — like 15% of 200.

Find the percentage increase or decrease from one value to another.

Calculate the exact hydration percentage of your bread dough based on flour and liquid ratios.

Estimate the alcohol by volume and attenuation of your beer or wine from original and final gravity.

Calculate the tip, total bill, and per-person split for any restaurant check.

Estimate your monthly payment and total interest for any fixed-rate loan.

Estimate your monthly mortgage payment and total interest from home price, down payment, rate, and term.

See how your savings or investment grows over time with compound interest.

Convert your hourly wage into weekly, monthly, and annual salary figures instantly.

Estimate your monthly car payment including down payment and trade-in value.

Calculate the value of a certificate of deposit at maturity from its APY and term.

Find out how much to save each month to reach your savings goal on time.

Project how much a purchase will cost, and what today's money will be worth, at a given inflation rate.

Estimate your retirement balance from your current savings, monthly contributions, and expected return.

Find out exactly what score you need on your final exam to reach your target grade.

Calculate your Grade Point Average from course grades and credit hours on a 4.0 scale.

Add up your assignments, tests, and their weights to see your current class grade.

Calculate your exact age in years, months, and days from your date of birth.

Count the exact number of days and weeks between any two calendar dates.

Count the hours and minutes between two times, including overnight shifts.

Count down the days until any date — birthdays, holidays, deadlines, and more.

Calculate your Body Mass Index (BMI) from your height and weight in metric units.

Calculate your daily calorie needs (TDEE) and basal metabolic rate using the Mifflin-St Jeor equation.

Estimate your baby's due date and how far along you are from your last menstrual period.

Find the best time to go to bed based on your wake-up time and 90-minute sleep cycles.

Estimate your body fat percentage using the US Navy circumference method.

Calculate your running pace per kilometer and per mile from distance and time.

Work out how much concrete you need for a slab, in volume and 80 lb bags.

Estimate how much paint you need to cover the walls of a room, per coat.

Calculate the area of any rectangular space for flooring, tiling, or landscaping.

Work out how many pavers you need for a patio or walkway, including a waste allowance for cuts.

Convert a bed's area and depth into the cubic yards, cubic feet, and bags of mulch or soil to order.

Plan a fence run: how many posts, sections, and bags of concrete you need for the footings.

Find your odds of getting a drop over many attempts, and how many tries it takes to be reasonably sure.

Calculate damage per second from your hit damage, attack speed, and critical hit stats.

Find your effective DPI (eDPI) from your mouse DPI and in-game sensitivity to compare aim settings.

Calculate your win rate from wins and losses, and how many wins in a row you need to reach a target.

Find the odds of drawing the cards you need in an opening hand, for any trading card or deck-building game.

See how advantage and disadvantage change your d20 success chance against a target number in tabletop RPGs.

Price your handmade products for a sustainable profit margin after materials, labor, and marketplace fees.