Skip to main content
SlapMyWeb
Get started
Skip to tool
Conversion tools/All tools
Free tool

Unit converter

Convert between length, weight, volume, speed, area, data, temperature, time, and energy units instantly.

result

1 Millimeter (mm) = 0.1 Centimeter (cm)

1 Millimeter = 0.1 Centimeter

What is Unit Converter?

A unit converter is a tool that translates measurements from one unit system to another — for example, converting kilometers to miles, Celsius to Fahrenheit, or kilojoules to calories. This free online unit converter covers nine major categories: length, weight, volume, speed, area, data storage, temperature, time, and energy, with over 70 individual units. Temperature conversions use proper formulas (not simple multiplication), and all conversions happen in real time as you type. The tool shows the exact conversion formula so you understand the math behind every result. Whether you are a developer calculating file sizes, a student solving physics problems, an engineer converting metric to imperial, or a cook scaling recipes, this converter handles it all in one place.

How to Use Unit Converter

  1. 1

    Select a category

    Choose from Length, Weight, Volume, Speed, Area, Data, Temperature, Time, or Energy using the category tabs. Each category loads its own set of units relevant to that measurement type.

  2. 2

    Pick your units and enter a value

    Select the source unit in the From dropdown and the target unit in the To dropdown. Type a number in the value field. Use the swap button to quickly reverse the conversion direction.

  3. 3

    Read and copy the result

    The converted value appears instantly below the input along with the conversion formula. Click the Copy button to copy the full conversion result to your clipboard.

Features

  • Nine conversion categories: length, weight, volume, speed, area, data, temperature, time, energy
  • Over 70 units with precise conversion factors
  • Temperature: Celsius, Fahrenheit, Kelvin with correct formulas
  • Time: milliseconds to years including months and weeks
  • Energy: joules, calories, BTU, watt-hours, electron-volts
  • Real-time conversion that updates instantly as you type
  • One-click swap button to reverse from and to units
  • Displays the conversion formula for every conversion

Related Tools

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and back. Supports seconds and milliseconds.

Open tool

Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal bases instantly.

Open tool

Temperature Converter

Convert between Celsius, Fahrenheit and Kelvin with instant results and formula display.

Open tool

Byte Converter

Convert between bytes, KB, MB, GB, TB and PB. Binary (1024) and decimal (1000) modes.

Open tool

Roman Numeral Converter

Convert Roman numerals to Arabic numbers and back. Supports values up to 3999.

Open tool

Binary to Text Converter

Convert binary code to ASCII text and text to binary. Supports 8-bit encoding.

Open tool
See all Conversion tools

Frequently Asked Questions

How does temperature conversion work?+
Unlike other units, temperature uses formulas instead of simple multiplication. Celsius to Fahrenheit: F = C x 9/5 + 32. Celsius to Kelvin: K = C + 273.15. The tool applies the correct formula for each direction automatically.
Are the data storage conversions binary or decimal?+
This tool uses binary (base-1024) conversions for data storage units, which is the standard used by operating systems. So 1 KB = 1,024 bytes, 1 MB = 1,024 KB, and so on.
What is the difference between calories and kilocalories?+
A kilocalorie (kcal) equals 1,000 calories. The "calories" on food labels are actually kilocalories. In this tool, cal = small calorie (4.184 J) and kcal = food calorie (4,184 J).
How precise are the conversions?+
The tool uses high-precision conversion factors and displays results with up to 12 significant digits. For everyday use this provides more than enough accuracy.
What is a BTU?+
A British Thermal Unit (BTU) is the amount of heat needed to raise 1 pound of water by 1 degree Fahrenheit. It equals approximately 1,055 joules. BTU is commonly used in HVAC, heating, and energy industries.
Can I convert between categories?+
No. Each category represents a different physical quantity, so you cannot convert meters to kilograms. The swap button only works within the same category.