Everyday & Math
The quick math you reach for constantly — percentages, tips, discounts, sales tax, averages, ratios, GPA — each one a transparent formula with a worked example you can check, not a black box. Built to give the right answer in seconds and show you exactly how it got there.
- Everyday & MathLivePercentage CalculatorWork out what X% of a number is, what percentage one number is of another, or the percent change between two values. Three modes, one calculator.
- Everyday & MathLivePercentage Change CalculatorMeasure the percentage increase or decrease from an old value to a new one. Shows the signed percent change and the raw difference between the two figures.
- Everyday & MathLiveTip CalculatorWork out the tip, the grand total, and each person's share. Enter the bill, the tip percentage, and how many people are splitting it.
- Everyday & MathLiveDiscount CalculatorFind the sale price after a percentage off, and see exactly how much you save. Enter the original price and the discount percent.
- Everyday & MathLiveSales Tax CalculatorAdd sales tax to a subtotal and see the tax amount and grand total. Enter the pre-tax price and your local sales-tax rate.
- Everyday & MathLiveRatio CalculatorReduce a ratio like 12:8 to its simplest form and solve a proportion for a missing term. Enter two ratio terms and one known value.
- Everyday & MathLiveFraction CalculatorAdd, subtract, multiply, or divide two fractions and get the answer reduced to its simplest form. Enter each numerator and denominator.
- Everyday & MathLiveAverage CalculatorFind the average (arithmetic mean) of up to six numbers. Enter your values and see the mean, the count, and the total.
- Everyday & MathLiveStandard Deviation CalculatorFind the standard deviation of a data set — both the sample (n−1) and population (n) versions — plus the mean. Enter up to eight numbers.
- Everyday & MathLiveLCM and GCD CalculatorFind the greatest common divisor (GCD) and least common multiple (LCM) of two whole numbers using Euclid's algorithm. Enter two integers.
- Everyday & MathLiveCross-Multiply CalculatorSolve a/b = c/x for the missing value by cross-multiplying. Enter the three known numbers and get the fourth — the classic rule of three.
- Everyday & MathLiveGPA CalculatorCalculate your weighted GPA on a 4.0 scale from your course grades and credit hours. Enter each course's grade points and credits.
- Everyday & MathLiveGrade CalculatorCombine assignment, quiz, and exam scores by their weights into one overall course grade and letter. Enter each score and its weight.
- Everyday & MathLiveMarkup and Margin CalculatorTurn a cost and a selling price into markup percentage, margin percentage, and profit. See why markup and margin differ for the same sale.
- Everyday & MathLiveScientific Notation ConverterConvert a plain decimal number into normalised scientific notation (a × 10^n), with a coefficient between 1 and 10 and the power of ten.
- Everyday & MathLiveSquare Footage CalculatorFind the area of a rectangular room or space from its length and width, in square feet and square yards. Pure area arithmetic.
- Everyday & MathLivePizza Value CalculatorCompare two pizzas by price per square inch and find the better deal. Enter the diameter, price, and quantity of each option to see which gives more pizza.
- Everyday & MathLiveScreen Time to Years of Your Life CalculatorHow many years of your life will you spend looking at screens? Enter your daily screen hours and your age to see the projected total over the years you have left.