Unit Converter

A Unit Converter is a free tool that changes a measurement from one unit into another—across length, weight/mass, temperature, area, volume, speed, time, and digital storage. Pick a category, choose your from and to units, and type a value; the result appears instantly, works in both directions, and shows the exact factor or formula it used.

Everything runs entirely in your browser with JavaScript. There are no page reloads, no API calls, and nothing you type is ever sent to a server, so conversions are instant and completely private.

How to use the unit converter

1. Choose a category at the top—Length, Weight/Mass, Temperature, Area, Volume, Speed, Time, or Digital Storage.
2. Pick the unit you are converting from and the unit you are converting to in the two dropdowns.
3. Type a number into either the From or the To field—conversion is bidirectional, so editing either side updates the other live.
4. Read the formula line below the fields to see the conversion factor or temperature formula being applied.
5. Use the swap button to reverse the direction, or copy the result with one click.

What units can you convert?

The converter groups related units into eight categories so the dropdowns stay short and relevant:

• Length — millimetres to kilometres, plus inches, feet, yards, miles, and nautical miles.
• Weight / Mass — milligrams, grams, kilograms, tonnes, ounces, pounds, and stone.
• Temperature — Celsius, Fahrenheit, and Kelvin using true offset formulas, not a flat ratio.
• Area — square millimetres through square kilometres, plus acres and hectares.
• Volume — millilitres, litres, cubic metres, and US teaspoons, cups, pints, quarts, and gallons.
• Speed — metres per second, km/h, mph, feet per second, and knots.
• Time — milliseconds up to years, useful for durations and rate calculations.
• Digital Storage — bits and bytes through terabytes, with both decimal (KB) and binary (KiB) units.

How does temperature conversion work?

Most units convert through a single base unit multiplied by a fixed factor—one metre is always 3.28084 feet, for example. Temperature is different because its scales do not share a zero point. Converting Celsius to Fahrenheit uses °F = °C × 9/5 + 32, and Celsius to Kelvin uses K = °C + 273.15. This tool applies those proper formulas instead of a naive multiplier, so 0 °C correctly becomes 32 °F rather than 0.

Why use this unit converter?

It is fast, private, and transparent: every result is paired with the exact factor or formula used, which is handy for homework, engineering checks, cooking, travel, and file-size math. Because the logic is pure vanilla JavaScript with no libraries, it stays responsive and keeps working even after you go offline. If you work with raw numeric bases rather than measured quantities, a Number Base Converter handles binary, octal, decimal, and hexadecimal instead, and designers reaching for color values can turn hex codes into channels with a Hex to RGB Converter.

When to reach for a different converter

This tool is built for physical measurements and storage sizes, so use it whenever you are turning one unit of the same quantity into another. For a specific point in time rather than a duration, a Unix Timestamp Converter translates epoch seconds into human-readable dates, which the Time category here does not attempt. And if you are measuring the length of written text rather than a physical length, a Word Counter tallies words and characters instead of metres and feet.

Frequently Asked Questions

What unit categories does this converter support?

It covers eight categories: Length, Weight/Mass, Temperature, Area, Volume, Speed, Time, and Digital Storage. Each category has its own set of common units so the dropdowns stay focused and relevant.

Is the conversion bidirectional?

Yes. You can type into either the From or the To field and the opposite side updates instantly. A swap button also lets you reverse the two chosen units in one click.

How is temperature handled?

Temperature uses proper formulas rather than a single multiplier because Celsius, Fahrenheit, and Kelvin do not share a zero point. For example, Fahrenheit is calculated as °C × 9/5 + 32, and Kelvin as °C + 273.15.

What is the difference between KB and KiB in the storage category?

KB (kilobyte) is decimal and equals 1,000 bytes, while KiB (kibibyte) is binary and equals 1,024 bytes. The converter includes both so you can match whichever convention a device or program uses.

Does it show the formula or factor used?

Yes. A line beneath the input fields displays the exact conversion factor for linear units, or the full formula for temperature, so you can see and verify how each result was produced.

Is my data sent anywhere?

No. Every conversion happens locally in your browser with JavaScript. Nothing is uploaded, logged, or stored, and the tool keeps working even if you go offline after the page loads.