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Examples: 100 meters to feet · 32 f to c · 10 gb to mb
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SI Base Units
The seven fundamental units that define the International System of Measurements.
| Base quantity | Unit | Symbol | Definition |
|---|---|---|---|
| Time | second | s | The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the cesium-133 atom. |
| Length | meter | m | The distance light travels in a vacuum in 1/299,792,458 of a second. |
| Mass | kilogram | kg | Defined by fixing the Planck constant h at 6.62607015×10⁻³⁴ J⋅s. |
| Electric current | ampere | A | Defined by fixing the elementary charge e at 1.602176634×10⁻¹⁹ C. |
| Thermodynamic temperature | kelvin | K | Defined by fixing the Boltzmann constant k at 1.380649×10⁻²³ J/K. |
| Amount of substance | mole | mol | Exactly 6.02214076×10²³ elementary entities (Avogadro number). |
| Luminous intensity | candela | cd | The luminous intensity in a given direction of a source emitting monochromatic radiation at 540×10¹² Hz with intensity 1/683 W/sr. |
Your Complete Free Online Unit Conversion Calculator & Tools
Welcome to RealConversionTools, the most comprehensive free online unit conversion calculator and tools suite available on the web. Whether you need a currency conversion for international business, a temperature conversion for cooking, or a metric conversion chart for engineering, our platform delivers fast, accurate results every time. We support every major category of units conversion so you can stop juggling multiple websites and bookmark one reliable destination.
Currency Converter & Exchange Rates
Our currency converter provides real-time exchange rates for all major world currencies including USD, EUR, GBP, JPY, INR, CAD, AUD, CHF, CNY, BRL, and ZAR. Need a quick euro to dollar conversion? Type "100 eur to usd" and get the exact amount based on live rates. The yen to dollar conversion, pound to dollar, and every other currency pair updates continuously so you always have accurate forex data for your international transactions, travel planning, or financial analysis.
Length Conversion Tools
Our length converter handles every unit you will ever need. The most popular query on our platform is mm to inches conversion, essential for engineering, woodworking, and 3D printing. We also offer cm to inches conversion for everyday measurements, meters to feet for construction, kilometers to miles for road trips, and even nautical miles for maritime navigation. Our precise conversion calculator uses exact conversion factors, so you never have to worry about rounding errors in critical measurements. The conversion chart feature gives you quick reference values at a glance.
Weight & Mass Conversion
The kg to lbs conversion is one of the most frequently used tools on our platform, vital for fitness, shipping, and international commerce. But we go far beyond that. Convert milligrams to grams, ounces to pounds, stones to kilograms, and metric tons to imperial tons. Whether you are a pharmacist measuring precise doses, a chef scaling recipes, or a logistics professional calculating shipping weights, our weight and mass tools deliver laboratory-grade accuracy through an intuitive interface.
Temperature Conversion
Our temperature converter handles celsius to fahrenheit conversion, kelvin, and rankine scales. The c to f conversion is essential for cooking, weather forecasting, and scientific work. We also support reverse conversion with equal precision — fahrenheit to celsius, kelvin to celsius, and everything in between. The formula is displayed alongside every result so you can learn the mathematics behind the temperature conversion while getting your answer instantly.
Volume, Speed, Time & More
Beyond the essentials, our suite includes a volume converter (liters, gallons, quarts, pints, cups, fluid ounces), speed converter (kmh to mph, knots, m/s), time converter (seconds to hours, days to weeks), energy converter (joules, calories, kWh, BTU), area converter (square meters, hectares, acres, square feet), power converter (watts, horsepower), pressure converter (pascal, psi, bar, atm, torr), angle converter (degrees, radians, gradians), and digital data converter (bytes, KB, MB, GB, TB, and binary units like KiB, MiB, GiB).
Metric Units Conversion & SI Standards
Our metric conversion chart and SI units conversion tools are designed for students, educators, and professionals who work with the International System of Units. We provide clear metric units conversion for all SI base and derived units, including the seven fundamental SI base units — second, meter, kilogram, ampere, kelvin, mole, and candela. Whether you need a scientific conversion calculator for physics homework or a pressure units conversion chart for industrial applications, our platform supports every common scientific and engineering unit. Specialized conversions such as ml to units, mg to units, and mcg to units ensure healthcare professionals can work confidently with pharmaceutical measurements.
Why RealConversionTools?
There are many conversion calculators online, but none combine the breadth of tools, precision, and user experience that we offer. Our search-powered interface lets you type natural queries like "32 f to c" or "10 gb to mb" and get instant results without navigating menus. All conversions happen client-side using high-precision floating-point mathematics, meaning there is zero latency — results appear as you type. We respect your privacy: no sign-up, no tracking, no data collection. Just pure, accurate unit conversion tools that work offline and at the speed of thought. Bookmark RealConversionTools for all your measurement conversion needs, from everyday household conversions to complex scientific and engineering calculations.
All Supported Units
Every unit available across all 13 conversion categories.
- US Dollar $
- Euro €
- British Pound £
- Japanese Yen ¥
- Canadian Dollar C$
- Australian Dollar A$
- Swiss Franc CHF
- Chinese Yuan ¥
- Indian Rupee ₹
- Brazilian Real R$
- South African Rand R
- Mexican Peso $
- Singapore Dollar S$
- New Zealand Dollar NZ$
- Hong Kong Dollar HK$
- Swedish Krona kr
- South Korean Won ₩
- Russian Ruble ₽
- Turkish Lira ₺
- UAE Dirham د.إ
- Saudi Riyal ر.س
- Philippine Peso ₱
- Indonesian Rupiah Rp
- Thai Baht ฿
- Liter L
- Milliliter mL
- Cubic Centimeter cm³
- Cubic Meter m³
- US Gallon gal
- US Quart qt
- US Pint pt
- US Cup cup
- US Fluid Ounce fl oz
- US Tablespoon tbsp
- US Teaspoon tsp
- Imperial Gallon imp gal
- Imperial Quart imp qt
- Imperial Pint imp pt
- Imperial Fluid Ounce imp fl oz
- Cubic Foot ft³
- Cubic Inch in³
- Meter m
- Kilometer km
- Decimeter dm
- Centimeter cm
- Millimeter mm
- Micrometer µm
- Nanometer nm
- Mile mi
- Yard yd
- Foot ft
- Inch in
- Nautical Mile nmi
- Light Year ly
- Astronomical Unit AU
- Parsec pc
- Kilogram kg
- Gram g
- Milligram mg
- Microgram µg
- Pound lb
- Ounce oz
- Stone st
- Metric Ton t
- US Ton US t
- Imperial Ton UK t
- Carat ct
- Celsius °C
- Fahrenheit °F
- Kelvin K
- Rankine °R
- Joule J
- Kilojoule kJ
- Megajoule MJ
- Calorie cal
- Kilocalorie kcal
- Watt-hour Wh
- Kilowatt-hour kWh
- British Thermal Unit BTU
- Electronvolt eV
- Erg erg
- Foot-pound ft-lb
- Square Meter m²
- Square Kilometer km²
- Square Centimeter cm²
- Square Millimeter mm²
- Hectare ha
- Are a
- Acre ac
- Square Foot sq ft
- Square Inch sq in
- Square Yard sq yd
- Square Mile sq mi
- Meter per second m/s
- Kilometer per hour km/h
- Mile per hour mph
- Knot kn
- Foot per second ft/s
- Inch per second in/s
- Mach (Speed of Sound) Ma
- Second s
- Millisecond ms
- Microsecond µs
- Nanosecond ns
- Minute min
- Hour h
- Day d
- Week wk
- Month (30 days) mo
- Year (365 days) yr
- Decade dec
- Century c
- Watt W
- Milliwatt mW
- Kilowatt kW
- Megawatt MW
- Gigawatt GW
- Horsepower (mechanical) hp
- BTU per hour BTU/h
- Metric Horsepower (PS) PS
- Bit bit
- Byte B
- Kilobyte KB
- Megabyte MB
- Gigabyte GB
- Terabyte TB
- Petabyte PB
- Kibibyte KiB
- Mebibyte MiB
- Gibibyte GiB
- Tebibyte TiB
- Pebibyte PiB
- Pascal Pa
- Kilopascal kPa
- Megapascal MPa
- Hectopascal hPa
- Bar bar
- Millibar mbar
- Pound per sq inch psi
- Atmosphere atm
- Torr Torr
- Millimeter of Mercury mmHg
- Inch of Mercury inHg
- Degree °
- Radian rad
- Milliradian mrad
- Gradian grad
- Arcminute '
- Arcsecond "
- Revolution / Turn rev
Frequently Asked Questions
Quick answers to common questions about our conversion calculator tools.