Everyday Tools Calculators
Fast everyday calculators for percentages, discounts, rounding and common numerical questions, with instant answers and plain-language working.
Choose the calculation that matches the question before entering values: a percentage of a number, a relative change and a percentage-point change are not the same. Each tool shows the relevant method so the result can be checked rather than accepted as a black box.
How to use these calculators well
- Identify whether the question involves a percentage, percentage change or percentage points.
- Keep input units consistent and delay rounding until the final result.
- Use the displayed method to reproduce the answer independently.
Percentage Calculator
Calculate percentages, increases, decreases and one value as a percentage of another. Free instant results with clear formulas and examples.
Open calculatorPercentage Change Calculator
Calculate percentage change, increase or decrease, a percentage of a number, and what percent one value is of another. Free instant results.
Open calculatorRounding Calculator
Round positive or negative numbers to a chosen number of decimal places. See the rounded value and method instantly with a clear worked result.
Open calculatorAbsolute Value Calculator
Find the absolute value (distance from zero) of any positive or negative number instantly.
Open calculatorAge Calculator
Calculate an exact age in years or the precise difference between two calendar dates broken down into years, months, weeks and days for any occasion.
Open calculatorAverage Calculator
Calculate the mean of up to eight numbers, useful for averaging test scores, bills or measurements.
Open calculatorBMI and Health Calculator
Estimate your BMI, WHO weight category, healthy weight range, waist-based health risk and daily energy needs in kilojoules and kilocalories.
Open calculatorDate Difference Calculator
Work out the total days, business days, weeks, months and years between two dates, with optional weekend and national public holiday exclusions.
Open calculatorExponent Calculator
Raise a base number to any power, including negative or fractional exponents, and see the result instantly.
Open calculatorFactorial Calculator
Calculate the factorial of a whole number, useful for permutations, combinations and probability problems.
Open calculatorFraction to Percentage Calculator
Convert any fraction, such as marks out of a test or a recipe ratio, into a percentage instantly.
Open calculatorGreatest Common Divisor Calculator
Find the greatest common divisor (GCD) and lowest common multiple (LCM) of two whole numbers using the Euclidean algorithm.
Open calculatorLogarithm Calculator
Calculate the logarithm of a number to any base, including common log (base 10) and natural log (base e).
Open calculatorMedian Calculator
Find the median (middle value) of up to eight numbers, a useful measure of the centre that isn't skewed by outliers.
Open calculatorMode Calculator
Find the most frequently occurring value (or values) among up to eight numbers you enter.
Open calculatorNth Root Calculator
Calculate the nth root of a number, such as a cube root or fourth root, for any positive whole-number degree.
Open calculatorPaint Coverage Calculator
Work out paintable wall and ceiling area, litres of paint needed, tins to buy and total estimated cost, with editable door and window deductions.
Open calculatorPercentage Difference Calculator
Work out the percentage difference between two numbers, useful for comparing prices, scores or measurements quickly.
Open calculatorPercentage to Fraction Calculator
Convert a percentage into its simplest fraction form, showing both the raw and simplified fractions.
Open calculatorProportion Calculator
Solve for the missing value in a proportion, such as scaling ingredients or converting rates, using cross-multiplication.
Open calculatorRange Calculator
Calculate the statistical range — the difference between the highest and lowest of up to eight numbers.
Open calculatorRatio Calculator
Simplify a ratio of two or three numbers to its lowest terms, useful for recipes, mixing solutions or scaling drawings.
Open calculatorReverse Percentage Calculator
Find the original value before a percentage increase or decrease was applied, handy for working backwards from a sale price or tax-inclusive figure.
Open calculatorScientific Notation Calculator
Convert a number between standard decimal form and scientific notation, showing the exponent and coefficient clearly.
Open calculatorSquare Root Calculator
Find the square root of a number, with a clear error message for negative inputs since real square roots don't exist for them.
Open calculatorUnit Conversion Calculator
Convert length, weight, volume, area, temperature, speed and fuel economy units, including litres per 100km, km per litre and miles per gallon.
Open calculatorWeighted Average Calculator
Calculate a weighted average from up to four value and weight pairs, ideal for grades where assessments carry different weightings.
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