Math & number converters
Fractions and decimals, inch fractions, Roman numerals, scientific notation, binary, hex and angles. Every tool below is free, works instantly in your browser and explains the formula behind the result.
Number conversions come up in homework, woodworking, programming and everyday measuring. Convert fractions to decimals (including repeating decimals) and back, read decimal inches as tape-measure fractions, translate Roman numerals, write numbers in scientific notation, switch between binary, decimal and hexadecimal, and convert angles between degrees and radians — each with a step-by-step explanation.
19 tools in this category
- Fraction to Decimal ConverterConvert any fraction or mixed number to a decimal and a percentage.
- Decimal to Fraction CalculatorConvert a decimal such as 0.375 or 2.625 into a fraction in lowest terms, plus a mixed number and the closest simple fraction for long or repeating decimals.
- Decimal to Fraction Inches CalculatorTurn decimal inches or millimeters into the nearest fraction of an inch you can find on a tape measure or ruler — to the nearest 1/8, 1/16, 1/32 or 1/64.
- Roman Numeral ConverterConvert any number from 1 to 3,999 into Roman numerals, or read a Roman numeral as a number.
- Scientific Notation ConverterWrite very large or very small numbers in scientific notation, E notation or engineering notation — or convert them back into an ordinary number.
- Binary to Decimal ConverterConvert numbers between binary (base 2) and decimal (base 10), with hexadecimal and octal shown too.
- Hex to Decimal ConverterConvert hexadecimal (base 16) numbers to decimal and back, with binary and octal shown as well.
- Degrees to Radians ConverterConvert angles between degrees and radians.
- Percent to Decimal ConverterConvert between percentages, decimals and fractions — for example 45% = 0.45 = 9/20.
- DMS to Decimal Degrees ConverterConvert map coordinates between degrees, minutes and seconds (40° 26′ 46″ N) and decimal degrees (40.446111) for GPS, Google Maps and GIS.
- Degrees to Percent Slope ConverterConvert a slope between degrees, percent grade and a rise : run ratio — useful for ramps, driveways, roads, roofs and hiking trails.
- Octal ConverterConvert numbers to and from octal (base 8).
- Radians to Degrees ConverterConvert an angle in radians to degrees.
- Online ProtractorEnter an angle to see it drawn on a protractor, along with its type, radians and complementary and supplementary angles.
- Compass Degrees to Direction ConverterTurn a bearing in degrees — from a compass, GPS or wind report — into a compass direction such as SW or NNE.
- How to Convert a Decimal to a FractionChanging a decimal to a fraction takes three steps: write the digits over a power of ten, find the greatest common divisor, and divide.
- Repeating Decimal to Fraction CalculatorEnter the digits before the repeat and the digits that repeat forever.
- Decimal to Fraction ChartA complete decimal to fraction conversion chart.
- Decimal to Fraction WorksheetForty decimal to fraction practice questions in four levels, with an answer key.
Other categories
- Temperature converters
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