Education & Maths Calculators

Fractions & Ratios

• Cross Multiplication Calculator

  Compare A/B with C/D by calculating their two cross products.

• Decimal to Fraction Converter

  Approximate a finite decimal as a reduced fraction, with a maximum denominator you choose.

• Decimal to Percentage Converter

  Convert a decimal proportion to a percentage by multiplying it by 100.

• Direct Proportion Calculator

  Calculate a new output under direct proportion from a known input-output pair and a new input.

• Fraction Comparison Calculator

  Compare two signed fractions and identify the larger value using exact integer cross-products.

• Fraction Difference Calculator

  Subtract the second fraction from the first and return a reduced signed fraction.

• Fraction Simplifier

  Reduce a fraction to lowest terms while keeping its value and a positive denominator.

• Fraction to Decimal Converter

  Convert a signed whole-number fraction to a decimal, rounded to at most eight decimal places.

• Fraction to Percentage Converter

  Express a signed fraction as a percentage of one whole.

• Improper Fraction to Mixed Number Converter

  Convert a signed improper fraction into a whole part and a reduced remainder fraction.

• Inverse Proportion Calculator

  Calculate a new output when input and output have a constant product.

• Missing Ratio Value Calculator

  Find D in A:B = C:D from three nonzero terms.

• Mixed Number to Improper Fraction Converter

  Convert a whole number and fractional part into one reduced improper fraction.

• Percentage Change Calculator

  Calculate the signed percentage change from an original value to a new value.

• Percentage Decrease Calculator

  Apply a stated percentage decrease to a number and return the resulting value.

• Percentage Increase Calculator

  Apply a percentage increase to an original number and return the updated value.

• Percentage of a Number Calculator

  Find a chosen percentage of a number, including decimal percentages.

• Percentage to Decimal Converter

  Convert percentage notation into a decimal proportion by dividing by 100.

• Proportion Calculator

  Solve A/B = C/D for the missing D using three known nonzero values.

• Ratio Comparison Calculator

  Compare two signed ratios as exact decimal quotients.

• Ratio Scale Calculator

  Multiply both terms of a ratio by the same nonzero factor.

• Ratio Simplifier

  Reduce a pair of signed whole-number ratio terms by their greatest common divisor.

• Ratio to Percentage Calculator

  Express Part divided by Whole as a percentage.

• Reverse Percentage Calculator

  Recover an original value when a known final value is a stated percentage of that original.

• Scale Factor Calculator

  Find the length scale factor between a positive original measurement and a non-negative new measurement.

Geometry

• Circle Area Calculator

  Find the area inside a circle from its radius.

• Circle Area Difference Calculator

  Compare the areas of two circles from their radii.

• Circle Circumference Calculator

  Find the distance around a circle from its radius.

• Circle Radius or Diameter Calculator

  Recover a circle’s radius and diameter from a known area or circumference.

• Circle Scale Calculator

  Scale a circle’s radius and diameter by a non-negative factor.

• Cylinder Base Circumference Calculator

  Calculate the distance around a cylinder’s circular base from its radius.

• Cylinder Height From Volume Calculator

  Find the height of a right circular cylinder from its volume and base radius.

• Cylinder Scale Calculator

  Scale the radius and height of a right circular cylinder by the same non-negative factor.

• Cylinder Surface Area Calculator

  Calculate the total exterior area of a closed right circular cylinder from its radius and height.

• Cylinder Surface Area Difference Calculator

  Subtract one cylinder surface area from another to find a signed change.

• Rectangle Area Calculator

  Calculate the flat area of a rectangle from its length and width.

• Rectangle Area Difference Calculator

  Compare two rectangular areas from their lengths and widths.

• Rectangle Missing Dimension Calculator

  Find a rectangle’s unknown side from its area and the other side length.

• Rectangle Perimeter Calculator

  Find the distance around a rectangle from its length and width.

• Rectangle Scale Calculator

  Multiply a rectangle’s length and width by the same non-negative scale factor.

• Right Triangle Area Calculator

  Calculate a right triangle’s area from its two perpendicular legs.

• Right Triangle Area Difference Calculator

  Find the signed difference between two known right-triangle areas.

• Right Triangle Missing Dimension Calculator

  Find a right triangle’s hypotenuse from two legs, or its missing leg from a hypotenuse and one leg.

• Right Triangle Perimeter Calculator

  Calculate a right triangle’s perimeter from its two positive perpendicular legs.

• Right Triangle Scale Calculator

  Scale the two perpendicular legs of a right triangle by the same non-negative factor.

• Triangle Area Calculator

  Find a triangle’s area from its base and perpendicular height.

• Triangle Area Difference Calculator

  Subtract two known triangle areas to find the signed change.

• Triangle Height From Area Calculator

  Find a triangle’s perpendicular height from its area and a positive base length.

• Triangle Perimeter Calculator

  Add three positive side lengths to find a triangle’s perimeter.

• Triangle Scale Calculator

  Scale a triangle’s base and perpendicular height by the same non-negative factor.

Grades

• Course Grade Average Calculator

  Average comparable course grades with equal weighting, or supply a matching list of non-negative weights.

• Course Grade Difference Calculator

  Compare two course grade percentages.

• Course Grade Percentage Calculator

  Calculate a course grade percentage from points earned and points available.

• Course Grade Points Needed Calculator

  Find the additional points needed to reach a target course grade percentage of a known final point total.

• Course Grade Target Score Calculator

  Find the score needed on future work to reach a target course grade percentage.

• Exam Score Average Calculator

  Average comparable exam scores with equal weighting, or supply a matching list of non-negative weights.

• Exam Score Difference Calculator

  Compare two exam score percentages.

• Exam Score Percentage Calculator

  Calculate an exam score percentage from points earned and points available.

• Exam Score Points Needed Calculator

  Find the additional points needed to reach a target exam score percentage of a known final point total.

• Exam Target Score Calculator

  Find the score needed on future work to reach a target exam score percentage.

• Homework Points Needed Calculator

  Find the additional points needed to reach a target homework score percentage of a known final point total.

• Homework Score Average Calculator

  Average comparable homework scores with equal weighting, or supply a matching list of non-negative weights.

• Homework Score Difference Calculator

  Compare two homework score percentages.

• Homework Score Percentage Calculator

  Calculate a homework score percentage from points earned and points available.

• Homework Target Score Calculator

  Find the score needed on future work to reach a target homework score percentage.

• Quiz Score Average Calculator

  Average comparable quiz scores with equal weighting, or supply a matching list of non-negative weights.

• Quiz Score Difference Calculator

  Compare two quiz score percentages.

• Quiz Score Percentage Calculator

  Calculate a quiz score percentage from points earned and points available.

• Quiz Score Points Needed Calculator

  Find the additional points needed to reach a target quiz score percentage of a known final point total.

• Quiz Target Score Calculator

  Find the score needed on future work to reach a target quiz score percentage.

• Test Points Needed Calculator

  Find the additional points needed to reach a target test score percentage of a known final point total.

• Test Score Average Calculator

  Average comparable test scores with equal weighting, or supply a matching list of non-negative weights.

• Test Score Difference Calculator

  Compare two test score percentages.

• Test Score Percentage Calculator

  Calculate a test score percentage from points earned and points available.

• Test Target Score Calculator

  Find the score needed on future work to reach a target test score percentage.

Statistics

• Measurements Mean Calculator

  Find the arithmetic mean of a set of measurements taken in the same unit.

• Measurements Median Calculator

  Find the middle of a set of measurements without letting one extreme reading control the result.

• Measurements Percentile Calculator

  Find a selected percentile of your measurements using inclusive linear interpolation.

• Measurements Range Calculator

  Find the gap between your largest and smallest measurements.

• Measurements Standard Deviation Calculator

  Measure how widely your readings vary around their mean using population or sample standard deviation.

• Number Set Mean Calculator

  Calculate the arithmetic mean of a number set, including negative values and decimals.

• Number Set Median Calculator

  Sort a number set and find its middle value or the average of its two middle values.

• Number Set Percentile Calculator

  Calculate a number-set percentile with the inclusive R-7 interpolation method.

• Number Set Range Calculator

  Subtract the smallest number in a set from the largest to find its range.

• Number Set Standard Deviation Calculator

  Calculate population or sample standard deviation for a list of numbers.

• Response Times Mean Calculator

  Calculate the average response time from a list of timings in one unit.

• Response Times Median Calculator

  Find the median response time to describe the middle observation in a timing sample.

• Response Times Percentile Calculator

  Calculate a response-time percentile, such as p95, from your recorded timings.

• Response Times Range Calculator

  Find the difference between the slowest and fastest recorded response times.

• Response Times Standard Deviation Calculator

  Measure response-time variability with population or sample standard deviation.

• Test Results Mean Calculator

  Find the arithmetic mean of comparable test results on one scoring scale.

• Test Results Median Calculator

  Find the middle score in a list of comparable test results.

• Test Results Percentile Calculator

  Find a selected percentile within your supplied test results using inclusive interpolation.

• Test Results Range Calculator

  Calculate the difference between the highest and lowest test results.

• Test Results Standard Deviation Calculator

  Describe how test results vary around their mean using population or sample standard deviation.

• Weighted Sum Calculator

  Multiply each value by its matching weight and add the products.

• Weighted Values Mean Calculator

  Find a weighted mean from matching value and non-negative weight lists.

• Weighted Values Median Calculator

  Find the lower weighted median from matching values and non-negative weights.

• Weighted Values Percentile Calculator

  Find a weighted percentile using the cumulative weight of ordered observations.

• Weighted Values Standard Deviation Calculator

  Calculate weighted standard deviation with a stated population or frequency-weight sample convention.

Compare fraction representations

Convert the same numerator and denominator to a decimal and a percentage. Enter the original fraction in both tools to avoid carrying a rounded decimal into the second calculation.

1. 1. Fraction to decimal
2. 2. Fraction to percentage

Common questions