About these converters
A converter changes the same value into a different form. Miles become kilometers, Celsius becomes Fahrenheit, decimal becomes binary and a HEX color becomes RGB. The value is the same, only the way we write it changes.
These converters show the full set of results at once, so you can scan for the format you need. Where there are traps, such as US versus UK gallons, the tool labels them clearly.
What each tool does
- Unit Converter: Pick a category, choose the unit you have and the unit you want, then enter a value. The converter also lists the value in every other unit.
- Temperature Converter: To convert Celsius to Fahrenheit, multiply by 9/5 and add 32. To convert Fahrenheit to Celsius, subtract 32 and multiply by 5/9.
- Roman Numeral Converter: Roman numerals use the letters I, V, X, L, C, D and M for 1, 5, 10, 50, 100, 500 and 1000. Enter a number or a numeral to convert it either way.
- Number to Words Converter: Enter a number and the tool writes it in English words, for example 1,250 becomes One thousand two hundred and fifty. It supports decimals and negative numbers.
- Binary, Decimal and Hex Converter: Enter a number and its base. The converter shows the same value in binary (base 2), octal (8), decimal (10), hexadecimal (16) and base 36.
- Color Converter: Enter a HEX color code to see the matching RGB and HSL values, a live swatch and the contrast ratio against white and black text.
- Text to Binary Converter: Type text to get its binary or hexadecimal code, or paste binary or hex to read the text. It uses UTF8, so letters, symbols and emoji work.
- Morse Code Translator: Type plain text to get Morse code, or paste dots and dashes to read the message. The tool detects the direction for you.
- CSV to JSON Converter: Paste CSV data with a header row and the tool returns a JSON array of objects. It handles quoted fields, commas inside values and optional number detection.
- Markdown to HTML Converter: Type or paste Markdown to get HTML code and a live preview. It supports headings, bold, italic, links, images, lists, quotes, code and rules.
- Data Storage Converter: Enter a size and choose its unit to see it in every other storage unit. Decimal units use 1,000 steps and binary units use 1,024 steps.
- HTML Entity Encoder and Decoder: Paste text to turn characters such as less than, greater than, ampersand and quotes into safe HTML entities, or decode entities back into normal text.
- Length Converter: Enter a length, choose the units and read the exact conversion. A table shows the value in every other length unit.
- Weight Converter: Enter a weight, choose the units and read the exact result. A table shows the value in every other weight unit.
- Speed Converter: Enter a speed, choose the units and read the result. A table shows the value in km/h, mph, m/s and knots.
- Area Converter: Enter an area, choose the units and read the result. A table shows the value in every other area unit.
- Volume Converter: Enter a volume, choose the units and read the result. A table shows the value in every other volume unit.
- Pressure Converter: Enter a pressure, choose the units and read the exact result. A table shows the value in every other pressure unit.
- Energy Converter: Enter an amount of energy, choose the units and read the exact result. A table shows every other energy unit.
- Power Converter: Enter a power value, choose the units and read the exact result. A table shows every other power unit.
How to choose the right tool
For everyday measurements use the unit converter. For weather and cooking use the temperature converter. Developers can use the base and color converters. Writers and finance teams can use number to words for cheques and invoices.
If a conversion matters for safety, medicine or engineering, double check the factor with an official source.
Frequently asked questions
Are conversion factors exact?
They use standard definitions. Results show up to 8 decimals.
Do I need an internet connection?
Once the page has loaded, the conversion runs in your browser.
Do you convert currencies?
No, because exchange rates change every second.
Can I convert in bulk?
Not yet. Each tool converts one value at a time.
Need something we do not offer, such as page speed tests or keyword volume? See our directory of trusted free tools.