Free Online Unit Converters
Fast, accurate, and completely free online unit converters for length, weight, temperature, area, volume, pressure, speed, digital storage, and engineering metrics. Live bidirectional calculations, step-by-step formulas, and comprehensive reference lookup tables.
Available Unit Converters
Select any free unit converter below to perform instant bidirectional calculations.
Length Converter
Convert meters, cm, feet, inches, km and miles with our length converter.
Area Converter
Convert area instantly with our free area converter. Easily convert square feet to square meters, acres to sq ft, hectares, and 10+ units with exact formulas.
Volume Converter
Convert volume instantly with our free volume converter. Easily convert gallons to liters, ml to oz, cubic feet, cups, and 17+ units with exact formulas.
Weight & Mass Converter
Convert weight and mass instantly with our free weight converter. Easily convert kg to lbs, grams to oz, stones, metric tons, and 12+ units with exact formulas.
Temperature Converter
Convert temperature instantly with our free temperature converter. Easily convert Celsius to Fahrenheit, Kelvin, Rankine, and Réaumur with exact formulas.
Speed Converter
Convert speed instantly with our free speed converter. Easily convert mph to km/h, knots, m/s, ft/s, Mach, and speed of light with exact formulas.
Time Converter
Convert time instantly with our free time converter. Easily convert hours to minutes, seconds, days, weeks, ms, and 12+ units with exact formulas.
Digital Storage Converter
Convert digital storage instantly with our free storage converter. Easily convert MB to GB, TB, bits, bytes, KB, and binary IEC units (KiB, GiB) with formulas.
Data Transfer – Mbps to MB/s
Your internet plan is sold in Mbps (megabits per second), but your downloads show MB/s (megabytes per second). Enter any speed below to see what it really means. To convert by hand, divide Mbps by 8.
Energy Converter
Convert energy instantly with our free energy converter. Easily convert Joules, Calories, kWh, BTU, eV, and foot-pounds with exact formulas and tables.
Power Converter
Convert power instantly with our free power converter. Easily convert Kilowatts (kW) to Horsepower (hp), Watts, Megawatts, and BTU/hr with exact formulas.
Pressure Converter
Convert pressure instantly with our free pressure converter. Easily convert PSI to Bar, kPa to PSI, Pascals, Atm, and Torr with exact formulas and tables.
Force Converter
Convert force instantly with our free force converter. Easily convert Newtons to Pound-force (lbf), kN to Kips, kgf, and Dynes with exact formulas and tables.
Torque Converter
Convert torque instantly with our free torque converter. Easily convert Nm to ft-lbs, ft-lbs to Nm, in-lbs, and kgf-m with exact formulas and wrench tables.
Density Converter
Convert density instantly with our free density converter. Convert kg/m³ to g/cm³, lb/ft³, g/mL, and ppg with exact formulas and material density tables.
Frequency Converter
Convert frequency instantly with our free frequency converter. Easily convert Hz to kHz, MHz, GHz, THz, and RPM with exact formulas and reference tables.
Fuel Economy Converter
Convert fuel economy instantly with our free fuel consumption converter. Convert MPG (US), MPG (UK), km/L, and L/100km with exact formulas and vehicle tables.
Angle Converter
Convert angles instantly with our free angle converter. Easily convert degrees to radians, gradians, mrad, arcminutes, and MOA with exact formulas and tables.
Acceleration Converter
Convert acceleration units instantly with our free acceleration converter. Calculate m/s², g-force, ft/s², Gal, and mph/s with exact formulas and tables.
Try searching for keywords like "Length", "Weight", "Temperature", "Pressure", "GB", "Speed", or "Volume".
Why Choose OnlineConverter Unit Converters?
Laboratory-grade accuracy, instant client-side calculation, and 100% private conversions.
100% Private & Secure
In-browser computing. Your entered numbers, technical dimensions, and proprietary formulas are never transmitted to external servers.
SI & NIST Precision
Built with verified international NIST standards, exact fractional ratios, and high-precision floating-point arithmetic for zero rounding drift.
Instant Zero Latency
Instant bidirectional calculation as you type. Switch units or swap directions with zero page reloads and instant dynamic formulas.
Comprehensive Catalog
Full support for Metric (SI), Imperial, US Customary, nautical, astronomical, and physics units across 19 specialized tools.
How to Convert Units Online
Choose from length, weight, temperature, pressure, digital storage, volume, or 13 other converters above.
Type any numeric value and select your current starting unit from the intuitive dropdown menu.
Pick the destination unit to convert into. Results update instantly in real time as you type.
Copy the precision converted figure with one click and explore the detailed formula and step-by-step math.
About OnlineConverter Unit Converters Suite
OnlineConverter Unit Converters is a comprehensive, client-side measurement and conversion platform built for engineers, scientists, students, architects, culinary professionals, and international traders. Whether you need to convert metric meters into imperial feet and inches, calculate mechanical pressure from Pascals to PSI, convert digital gigabytes to mebibytes, or reconcile temperatures between Celsius, Fahrenheit, and Kelvin, our tools deliver laboratory-grade mathematical accuracy without server latency.
Comprehensive Measurement Domains
Our 19 specialized tools cover all core physical and computing measurement branches:
Everyday & Commercial Units
Seamlessly convert distances, body weight, recipes, parcel volumes, land acreage, and climate readings with Length Converter, Weight Converter, Temperature Converter, Area Converter, and Volume Converter.
Physics, Thermodynamics & Mechanical Engineering
Compute industrial stresses, heating loads, motor ratings, and rotational forces with Pressure Converter, Power Converter, Energy Converter, Force Converter, and Torque Converter.
Digital Computing, Networks & Chronometry
Reconcile binary and decimal storage, network throughput bandwidth, radio wave frequencies, and calendar epochs with Digital Storage Converter, Data Transfer Converter, Frequency Converter, and Time Converter.
Kinematics, Material Science & Geometry
Evaluate vehicular velocities, gravitational accelerations, vehicle efficiency, material densities, and trigonometric rotations using Speed Converter, Acceleration Converter, Fuel Economy Converter, Density Converter, and Angle Converter.
Metric (SI) vs. Imperial / US Customary Standards
The International System of Units (SI Metric) is based on decimal factors of 10, using universal base units including the meter, kilogram, second, and Kelvin. In contrast, the US Customary & British Imperial Systems trace their heritage to historical British trade definitions, relying on irregular bases (such as 12 inches per foot, 3 feet per yard, and 16 ounces per pound). Our conversion algorithms maintain exact reciprocal conversion factors to guarantee zero rounding drift when translating across systems.
OnlineConverter vs. Traditional Online Converters
| Feature | OnlineConverter | Traditional Online Converters |
|---|---|---|
| Calculation Latency | Instant Real-Time (0ms Client-Side) | Slow page reloads & server delays |
| Data Privacy | 100% Client-Side In-Browser | Values logged and sent to analytics servers |
| Mathematical Steps | Shows Complete Step-by-Step Formula | Final number only without explanation |
| Reference Lookup Tables | Interactive Multi-Unit Matrix | Single pair only or missing |
| Usage Limits & Cost | 100% Free Forever (No Sign-up) | Ad-heavy paywalls or limited queries |
Popular Unit Workflows
Convert meters, kilometers, feet, inches, and miles.
Convert kilograms, grams, pounds, ounces, and stones.
Convert Celsius, Fahrenheit, Kelvin, and Rankine.
Convert square meters, square feet, acres, and hectares.
Convert liters, milliliters, gallons, cups, and cubic meters.
Convert megabytes, gigabytes, terabytes, and gibibytes.
Convert Pascals, Bar, PSI, and standard atmospheres.
Frequently Asked Questions
Other Conversion Categories
Unit Converters Guides & Tutorials
Practical, step-by-step guides and tips for our free unit converters tools.
Decimal Hours Explained: How to Convert Time for Timesheets and Payroll
Decimal hours turn time into numbers like 7.75 or 38.3. To read them, multiply the decimal part by 60: 0.3 hours is 18 minutes and 7.75 hours is 7 hours 45 minutes. This guide includes a decimal hours chart, a timesheet example and the 7.30 vs 7:30 mistake, plus payroll rounding rules.
How Long Is 100 Minutes? Everyday Examples of Common Time Lengths
100 minutes is 1 hour 40 minutes, or 1.67 hours. That’s about the length of a typical feature film. This guide turns common minute values (75, 90, 120, 180, 300 and 1000 minutes) into hours, with real-life examples and a simple 2-step method to work it out yourself.
What Is Weight in Physics? Definition, Formula & Units
Weight in physics is the gravitational force acting on an object. It is calculated using W = m × g and measured in newtons (N). This guide explains the definition of weight, its formula and units, the difference between mass and weight, and simple calculation examples.
What Is Mass in Physics? Definition, Units & Examples
This blog explains what mass is in physics using simple definitions, SI units, measurement methods, real-life examples, and an easy comparison between mass and weight. It is designed for students and beginners who want a clear, practical understanding of mass without overly technical language.