Choose a calculator
For percentages, use the percentage calculator for X% of Y, and the percentage change calculator for increases, decreases and reversing a percent. For fractions and decimals, the decimal to fraction and fraction to decimal calculators convert both ways, and the fraction calculator adds, subtracts, multiplies and divides.
For data, the average calculator gives mean, median and mode, the standard deviation calculator gives spread, and the ratio calculator simplifies and splits. For science and school, the scientific notation converter handles very large and small numbers, and the grade and GPA calculators plan your results.
- Percentage Calculator – What Is X% of Y? – X% of Y, X is what % of Y, and X is Y% of what number.
- Percentage Change Calculator – Increase, Decrease and Reverse – Percent increase or decrease, add or subtract a percent, and find the original value.
- Decimal to Fraction Calculator – Exact and Closest Fractions – Decimal to exact fraction, mixed number and nearest 1/16, 1/32 or 1/64.
- Fraction to Decimal Calculator – With Repeating Decimals – Fraction or mixed number to decimal and percent, with repeating decimals.
- Fraction Calculator – Add, Subtract, Multiply and Divide Fractions – Add, subtract, multiply and divide fractions and mixed numbers, simplified.
- Average Calculator – Mean, Median, Mode and Range – Mean, median, mode, range and more for any list of numbers.
- Ratio Calculator – Simplify, Solve and Split by Ratio – Simplify ratios, solve proportions and split a total by a ratio.
- Standard Deviation Calculator – Sample and Population – Sample and population standard deviation, variance, mean and standard error.
- Scientific Notation Converter – Numbers to a × 10ⁿ and Back – Numbers to scientific, E and engineering notation, and back to decimals.
- Grade Calculator – Final Exam Score Needed and Weighted Grade – Final exam score needed for a target grade, and weighted course grade.
- GPA Calculator – Term and Cumulative Grade Point Average – Term and cumulative GPA from letter grades and credits on the 4.0 scale.
Frequently asked questions
Do the calculators round the answers?
Results are calculated in full precision and rounded only for display, usually to six decimal places. Fraction results are exact, reduced by the greatest common divisor.
How do I convert a percentage to a decimal or fraction?
Divide by 100 for the decimal, so 15% is 0.15. For the fraction, write the percentage over 100 and simplify, so 15% is 3/20. The percentage calculator also shows the fraction.
What is the difference between sample and population standard deviation?
Population standard deviation divides by n and is used when the data is the whole group. Sample standard deviation divides by n − 1 and is used when the data is a sample from a larger group.
Which grade scale does the GPA calculator use?
The common US 4.0 scale with plus and minus grades, where A is 4.0 and A- is 3.7. You can choose whether an A+ counts as 4.0 or 4.3. Weighted GPAs for honors or AP courses are not included, because schools differ.
Can I paste a list of numbers into the average calculator?
Yes. Separate the numbers with commas, spaces or semicolons, and the calculator handles up to 5,000 values.
Are these calculators suitable for homework?
They are useful for checking your own working, and each page shows the method. Follow your teacher's rules on calculators, and show your working where it is required.