Unit Conversion Calculators — Complete Reference
Need to convert between units? Our conversion calculators handle every measurement system — metric, imperial, US customary — with instant results and the underlying formula explained.
246+ calculators in this guide
Contents
- 1. Unit Conversions
- 2. Area Conversions
- 3. Length & Distance
- 4. Temperature
- 5. Decimal, Fraction & Percent
- 6. Other Conversions
- 7. Clothing and Sizing
- 8. Scientific Units
- 9. Everyday Conversions
- 10. Cooking Conversions
- 11. Digital and Computing
- 12. Medical Unit Conversions
- 13. Time Conversions
- 14. Extended Unit Converters
- 15. Related Guides & Articles
Unit Conversions
See all →Convert unit s instantly and accurately. Enter your value and unit — see the exact conversion with formula and common equivalents. Free.
Weight / Mass Converter
Convert between kg, lb, oz, g, stone, and all weight units instantly. Fast and accurate co
Length / Distance Converter
cm, m, ft, in, mi and more. Fast and accurate conversion with formula, worked examples and
Volume Converter
L, mL, gallons, cups and more. Fast and accurate conversion with formula, worked examples
Speed Converter
Convert between km/h, mph, m/s, knots, and all speed units instantly. Fast and accurate co
Energy Converter
Joules, calories, BTU and more. Fast and accurate conversion with formula, worked examples
Pressure Converter
Pa, psi, bar, atm and more. Fast and accurate conversion with formula, worked examples and
Power Converter
Watts, horsepower, BTU/hr and more. Fast and accurate conversion with formula, worked exam
Force Converter
Newton, pound-force, dyne and more. Fast and accurate conversion with formula, worked exam
Density Converter
kg/m³, g/cm³, lb/ft³ and more. Fast and accurate conversion with formula, worked examples
Angle Converter
Degrees, radians, gradians. Fast and accurate conversion with formula, worked examples and
Acceleration Converter
m/s², ft/s², g-force and more. Fast and accurate conversion with formula, worked examples
Metric Units Converter
Look up all metric unit prefixes from yotta (10²⁴) to yocto (10⁻²⁴). Enter your value and
Area Conversions
See all →Square meters, feet, acres and more. Formula, variable legend, diagram and worked example included. Instant geometry result.
Area Converter
All area unit conversions. Fast and accurate conversion with formula, worked examples and
Acres to Square Feet
Convert acres to square feet instantly with formula and worked examples. Fast and accurate
Square Feet to Acres
Convert square feet to acres instantly with formula and worked examples. Fast and accurate
Sq Feet to Sq Meters
Convert square feet to square metres instantly with formula and examples. Fast and accurat
Sq Meters to Sq Feet
Convert square metres to square feet instantly with formula and examples. Fast and accurat
Resistors in Series & Parallel
Calculate total resistance in circuits. See formula, variable legend, worked example and u
Pendulum Period Calculator
Calculate pendulum period and frequency. Formula, variable legend, worked example and step
Doppler Effect Calculator
Calculate observed frequency from Doppler effect. See formula, worked example and wave dia
Snell's Law Calculator
Apply Snell's Law to find the refracted angle at any interface. Enter angle of incidence a
Square Kilometers to Square Miles
Convert square kilometers to square miles instantly with formula and examples. Fast and ac
Hectares to Square Miles
Convert hectares to square miles and square kilometers. Fast and accurate conversion with
Roods to Acres Converter
Convert roods to acres and square meters. Fast and accurate conversion with formula, worke
Length & Distance
See all →Centimeters, inches, meters, feet and miles. Enter your figures — see the result with formula and year-by-year breakdown. Free.
Centimeters to Inches
Convert centimetres to inches instantly. Enter centimetres — get inches as a decimal and a
Inches to Centimeters
Convert inches to centimetres. Enter inches — get centimetres and millimetres with the exa
Meters to Feet
Convert metres to feet and inches with precision. Enter metres — get the exact feet and in
Height Converter
Convert height between ft/in and cm. Fast and accurate conversion with formula, worked exa
Kilograms to Pounds
Convert kilograms to pounds (lb) instantly with formula and reference table. Fast and accu
Pounds to Kilograms
Convert pounds to kilograms with the exact factor (1 lb = 0.4536 kg). Enter pounds — get k
Astronomical Unit Converter
Convert astronomical units to km, miles, and light-years. Fast and accurate conversion wit
Parsec Converter
Convert parsecs to light-years, kilometers, and miles. Fast and accurate conversion with f
Angstrom to Nanometer Converter
Convert angstroms to nanometers, micrometers, and picometers. Fast and accurate conversion
Fermi to Femtometer Converter
Convert fermi units to femtometers and picometers. Fast and accurate conversion with formu
Fathom to Meters Converter
Convert fathoms to meters, feet, and nautical miles. Fast and accurate conversion with for
League to Kilometers Converter
Convert leagues to kilometers, miles, and nautical miles. Fast and accurate conversion wit
Temperature
See all →Celsius, Fahrenheit, Kelvin and Rankine. Enter your values — see the result with formula, examples, and step-by-step working. Free.
Temperature Converter
Convert between all temperature scales. Fast and accurate conversion with formula, worked
Celsius to Fahrenheit
Convert Celsius to Fahrenheit instantly. Enter a temperature in °C — get the exact °F valu
Kelvin to Celsius
Convert Kelvin to Celsius and Fahrenheit instantly. Enter a Kelvin temperature — see °C an
Fahrenheit to Kelvin
Convert Fahrenheit to Kelvin instantly with formula and reference temperatures. Fast and a
Rankine to Fahrenheit Converter
Convert Rankine to Fahrenheit and Celsius. Fast and accurate conversion with formula, work
Newton to Celsius Converter
Convert Newton scale to Celsius and Fahrenheit. Fast and accurate conversion with formula,
Delisle to Celsius Converter
Convert Delisle scale to Celsius and Fahrenheit. Fast and accurate conversion with formula
Reaumur to Celsius Converter
Convert Reaumur scale to Celsius and Fahrenheit. Fast and accurate conversion with formula
Decimal, Fraction & Percent
See all →Convert between decimals, fractions, and percentages. Enter any form — see the equivalent decimal, fraction, and percentage instantly. Free.
Other Conversions
See all →Convert other s instantly and accurately. Enter your value and unit — see the exact conversion with formula and common equivalents. Free.
Roman Numeral Date
Convert any date to Roman numerals. Enter day, month, and year — see full Roman numeral da
Cooking Conversions
Cups, tablespoons, liters and more. Fast and accurate conversion with formula, worked exam
Volume Converter (Full)
Convert litres, gallons, cups, fl oz, cubic metres and more. Fast and accurate conversion
Speed Converter (Full)
mph, km/h, m/s, knots, Mach and feet per second. Fast and accurate conversion with formula
Pressure Converter (Full)
psi, Pa, bar, atm, mmHg and inHg conversions. Fast and accurate conversion with formula, w
Clothing and Sizing
See all →Dress Size Calculator
International dress size converter UK US EU. Fast and accurate result with formula, step-b
Shoe Size Converter
Shoe sizes UK US EU and cm conversions. Enter your values — see the result with formula, e
Ring Size Calculator
Ring size in UK US and EU standards. Enter your values — see the result with formula, exam
Hat Size Calculator
Hat size from head circumference measurement. Enter your values — see the result with form
Bra Size Calculator
Bra size from band and bust measurements. Enter your values — see the result with formula
Jeans Size Calculator
Jean size by waist and inseam measurement. Enter your values — see the result with formula
Suit Size Calculator
Mens suit size from chest and waist. Enter your values — see the result with formula, exam
Glove Size Calculator
Glove size from hand circumference. Enter your values — see the result with formula, examp
Children Clothing Size
International kids clothing size by age and height. Enter your values — see the result wit
Tire Size Calculator
Convert and compare tire size codes. Fast and accurate result with formula, step-by-step m
Dress Size US UK EU Converter
Convert dress sizes between US, UK, EU, and international sizes. Fast and accurate convers
Mens Shirt Size Converter
Convert mens shirt sizes between US, UK, EU, and chest measurements. Fast and accurate con
Scientific Units
See all →Joules to eV Converter
Convert joules to electron volts and vice versa. Fast and accurate result with formula, st
Frequency and Wavelength
Convert between frequency and wavelength for any wave. See formula, worked example and wav
Radiation Dose Converter
Convert between Gy Sv rem rad and mSv. Fast and accurate result with formula, step-by-step
Luminous Intensity
Convert candela lux lumens and footcandles. Fast and accurate result with formula, step-by
Flow Rate Calculator
Convert volume flow rate between unit systems. Fast and accurate result with formula, step
Torque Unit Converter
Convert Nm ft-lb kgf-m and in-oz. Formula, variable legend, worked example and step-by-ste
Viscosity Unit Converter
Dynamic and kinematic viscosity conversions. Enter your values — see the result with formu
Electron Volt to Joule Converter
Convert electron volts to joules and electron volts. Fast and accurate conversion with for
Calorie to kJ Converter
Convert between calories, kilocalories, and kilojoules. Fast and accurate conversion with
Bar PSI ATM Converter
Convert pressure between bar, psi, and atmospheres. Fast and accurate conversion with form
Tesla to Gauss Converter
Convert magnetic field strength between tesla and gauss. Fast and accurate conversion with
Henry to Millihenry Converter
Convert inductance between henry and millihenry. Fast and accurate conversion with formula
Everyday Conversions
See all →Fuel Cost Calculator
Convert everyday s instantly and accurately. Enter your value and unit — see the exact con
Knots to MPH
Convert knots to mph km/h and m/s. Full formula with variable legend, worked example and s
Mach Speed Calculator
Convert Mach numbers to mph and km/h. Fast and accurate result with formula, step-by-step
Paper Size Converter
Convert between A4 Letter Legal and other paper sizes. Fast and accurate result with formu
Pixel to CM Converter
Convert pixels to centimetres for any screen resolution. Enter pixels and DPI — get cm, mm
Roman Numeral Converter
Convert between Roman numerals and numbers. Fast and accurate result with formula, step-by
Download Time Calculator
Estimate download time for any file size and internet speed. Enter file size and speed — s
Battery Life Calculator
How long a battery lasts at given current draw. Enter your values — see the result with fo
Payment Processing Fee
Calculate PayPal, Stripe, and Square transaction fees to find your net payout. Instant res
Wind Chill Calculator
Feels-like temperature from air temperature and wind speed. Enter your figures — see the r
Heat Index Calculator
Apparent temperature from heat and relative humidity. Formula, worked example and unit con
Precious Metals Weight Converter
Convert troy ounces to grams, kilograms, and avoirdupois ounces. Enter troy oz — get preci
Cooking Conversions
See all →Cups to Grams Converter
Convert cups to grams for any ingredient. Enter the ingredient and volume — get the gram w
Grams to Cups Converter
Convert grams to cups for baking and cooking. Fast and accurate result with formula, step-
ml to Cups Converter
Convert millilitres to cups and tablespoons. Fast and accurate result with formula, step-b
Fluid Oz to ml
Convert US and UK fluid ounces to millilitres. Fast and accurate result with formula, step
Teaspoons to ml
Convert teaspoons and tablespoons to millilitres. Fast and accurate result with formula, s
Fahrenheit to Celsius
Oven temperature converter for baking. Fast and accurate result with formula, step-by-step
Cups to Grams - Sugar
Convert cups of sugar to grams instantly with formula and recipe conversions. Fast and acc
Butter Grams to Tablespoons
Convert butter from grams to tablespoons and sticks. Fast and accurate conversion with for
Honey Cups to Grams Converter
Convert honey from cups to grams and milliliters. Fast and accurate conversion with formul
Cocoa Powder Cups to Grams
Convert cocoa powder from cups to grams. Fast and accurate conversion with formula, worked
Altitude Baking Adjustment
Adjust baking recipe ingredients for high altitude cooking. Fast and accurate conversion w
Metric Cups to ml Converter
Convert metric cups to milliliters and liters. Fast and accurate conversion with formula,
Digital and Computing
See all →Hex to Binary Converter
Convert hexadecimal to binary and decimal. Enter a hex value — get the binary digits, deci
ASCII Converter
Convert between ASCII text and character codes. Fast and accurate conversion with formula,
Color Code Converter
Convert between HEX RGB HSL and CMYK color codes. Fast and accurate conversion with formul
IP Subnet Calculator
Subnet mask CIDR and available host calculation. Enter your values — see the result with f
Image Resolution Calculator
Image file size from resolution and bit depth. Instant conversion with formula, worked exa
Monitor DPI Calculator
Pixels per inch from screen size and resolution. Enter your values — see the result with f
Character Count Calculator
Count characters words and lines in any text. Enter your values — see the result with form
File Size Calculator
Estimate file size after compression or conversion. Instant conversion with formula, worke
Medical Unit Conversions
See all →mg to ml Calculator
Convert milligrams to millilitres for liquid medications. Fast and accurate result with fo
Units to ml Calculator
Convert insulin units to millilitres. Fast and accurate result with formula, step-by-step
mmHg to Pascal Converter
Convert blood pressure units mmHg Pa and atm. Fast and accurate result with formula, step-
Celsius to Kelvin
Convert between Celsius Kelvin and Rankine. Fast and accurate result with formula, step-by
Weight for Medical Use
Convert between kg lbs and stone for BMI and dosing. Fast and accurate result with formula
Time Conversions
See all →Hours to Days Calculator
Convert hours to days weeks and months. Fast and accurate result with formula, step-by-ste
Seconds to Minutes
Convert seconds to minutes hours and days. Fast and accurate result with formula, step-by-
Minutes to Hours
Convert minutes to hours and decimal hours. Fast and accurate result with formula, step-by
Months to Years
Convert months to years for age or duration. Fast and accurate result with formula, step-b
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and back. Enter a timestamp or date — see
Time Difference Calculator
Calculate time difference between any two cities or time zones. Enter locations — see the
Extended Unit Converters
See all →Frequency Converter Calculator
Professional frequency converter and analysis. Fast and accurate conversion with formula,
Torque Converter Calculator
Professional torque converter and analysis. Fast and accurate conversion with formula, wor
Viscosity Converter Calculator
Professional viscosity converter and analysis. Fast and accurate conversion with formula,
Flow Rate Converter Calculator
Professional flow rate converter and analysis. Fast and accurate conversion with formula,
Luminosity Converter Calculator
Professional luminosity converter and analysis. Fast and accurate conversion with formula,
Electrical Converter Calculator
Professional electrical converter and analysis. Fast and accurate conversion with formula,
Magnetic Field Converter Calculator
Professional magnetic field converter and analysis. Fast and accurate conversion with form
Radiation Converter Calculator
Professional radiation converter and analysis. Fast and accurate conversion with formula,
Fuel Consumption Converter Calculator
Professional fuel consumption converter and analysis. Fast and accurate conversion with fo
Paper Size Converter Calculator
Professional paper size converter and analysis. Fast and accurate conversion with formula,
Shoes Size Converter Calculator
Professional shoes size converter and analysis. Fast and accurate conversion with formula,
Bra Size Converter Calculator
Professional bra size converter and analysis. Fast and accurate conversion with formula, w
Related Guides & Articles
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