Free Online Unit Converter – Length, Distance, Weight & More
Use this Free Online Unit Converter to convert length, distance, weight, temperature, and volume instantly. This unit conversion online calculator supports kilometer to meter, mm into meter, pound to gram, liter to cubic meter, Fahrenheit to Celsius, and more.
This Free Online Unit Converter lets you convert length, distance, weight, temperature, and volume in just a second. Whether you need kilometer to meter, mm into meter, pound to gram, liter to cubic meter, or temperature conversions like Celsius to Fahrenheit, the tool gives fast and accurate results with zero manual effort.
It’s a lightweight unit conversion online calculator that works smoothly on mobile, tablet, and desktop.
Unit Converter
Quickly convert length, weight, temperature, and volume in one place.
Length Conversion Result
Weight Conversion Result
Temperature Conversion Result
Volume Conversion Result
How to Use the Unit Converter (3 Simple Steps)
Enter the Value
Type the amount you want to convert inside the Amount box.
Choose Units
Pick your category — length, distance, weight, temperature, or volume — and select your “from” and “to” units.
Get Instant Result
Press Convert. The unit converter calculator instantly shows the converted value using accurate formulas.
Free Online Unit Converter (All-in-One Tool)
This unit converter online calculator combines multiple converters into one place. Instead of opening separate tools for length, distance, weight, temperature, or volume, you get everything inside a single, easy interface.
Students, engineers, travelers, chefs, and business owners use this tool to speed up calculations, avoid mistakes, and smoothly convert between metric and imperial units.
Length & Distance Converter
Length Converter Calculator & Distance Converter Calculator
Convert between:
- meters, kilometers, centimeters, millimeters
- inches, feet, yards, and miles
Popular conversions include:
- kilometer to meter (km → m)
- mm into meter and mm into cm
- foot to meter / foot to kilometer
- foot to inch
- mile to kilometer
This makes the tool ideal for homework, construction measurements, travel planning, mapping, and engineering work.
Weight Converter
Weight Converter & Weight Converter Calculator
Supported units:
- kilogram (kg), gram (g), milligram (mg)
- pound (lb), ounce (oz)
Common conversions include:
- kilogram to gram
- pound to gram for parcels or recipes
- weight converter pound to kg
- weight converter lbs to kg
- weight converter lb to kg and ounces for mixed measurements
Perfect for fitness, cooking, ecommerce shipping, and packaging tasks.
Temperature Converter
Temperature Converter – F to C, C to F, & Kelvin
This section works as a complete temperature converter for:
- Celsius (°C)
- Fahrenheit (°F)
- Kelvin (K)
You can quickly convert:
- temperature converter F to C – useful for cooking or weather
- temperature converter Fahrenheit to Celsius – using the formula: (°F − 32) × 5/9
- celsius to fahrenheit – great for travel or oven settings
- celsius to kelvin – ideal for science labs
Many people search for celsius vs centigrade. Both names refer to the same scale, so the tool treats them equally.
Volume Converter
Volume Converter – Liters, Cubic Units & More
Supported units:
- liter (L)
- milliliter (mL)
- cubic meter (m³)
- cubic foot (ft³)
- gallon (US), quart, pint, cup, fluid ounce
Popular conversions include:
- liter to cubic meter
- liter to cubic feet
- liter to milliliter
- converting any unit back using the volume converter to liters function
The calculator applies standard formulas automatically, such as:
- 1 m³ = 1000 L
- 1 ft³ ≈ 28.316846592 L
- 1 US gallon ≈ 3.785411784 L
Volume Converter
Volume Converter – Liters, Cubic Units & More
The Volume tab turns this tool into a powerful volume converter for daily and professional work. Supported units include:
- liter (L)
- milliliter (mL)
- cubic meter (m³)
- cubic foot (ft³)
- gallon (US), quart (US), pint (US), cup (US), fluid ounce (US)
You can easily perform:
- liter to cubic meter – for tanks, storage, and engineering
- liter to cubic feet – for room volume and shipping
- liter to milliliter – for medicine doses and recipes
- volume converter to liters – convert any supported unit back into liters
If you need the convert volume to liters formula, the calculator uses standard relationships such as:
1 cubic meter = 1000 liters, 1 US gallon ≈ 3.785411784 liters, 1 ft³ ≈ 28.316846592 liters.
Why Use Our Free Online Unit Converter?
All Conversions in One Place
Handle length, distance, weight, temperature, and volume without switching between tools.
Accurate, Standard Formulas
Every conversion — from kilometer to meter to pound to gram — uses precise scientific relationships.
Saves Time Everywhere
Avoid manual math for kg to g, mm into cm, foot to meter, and similar daily conversions.
Metric & Imperial Supported
Move between kilograms and pounds, feet and meters, Celsius and Fahrenheit effortlessly.
Free, Fast & Mobile-Friendly
Works instantly across devices with no login or installation required.
FAQs: Free Online Unit Converter
It’s an all-in-one tool that handles length, distance, weight, temperature, and volume conversions — replacing separate tools like a length converter calculator, distance converter calculator, or weight converter calculator.
Yes. Select kilometer → meter for km → m, or mile → kilometer for mi → km.
Yes. Choose mm → m or mm → cm to convert millimeters instantly.
Select foot (ft) as the starting unit and choose meter (m), kilometer (km), or inch (in) as the output.
Yes. Choose pound (lb) → kilogram (kg) to convert both lbs to kg and pound to kg correctly.
Open the Temperature tab and select °C → °F or °C → K for accurate results.
There is no difference. Celsius and centigrade refer to the same temperature scale.
Yes. Select liter (L) → m³, ft³, or mL as needed.
It applies correct formulas automatically depending on the source unit.
Learn More About Unit Conversion
Related Calculators
Explore more free financial tools by Free Tool Mart:
QR Code Generator
Generate QR codes for websites, social profiles, Wi-Fi, contacts, and more — all with instant download options.
BMI Calculator
Find your Body Mass Index instantly using WHO-standard categories to understand your weight range.
Retirement Savings Calculator
Plan your retirement confidently by projecting savings goals, growth over time, and the impact of contributions, inflation, and expected returns.