Everyday calculations
Unit converter
Convert values across supported measurement categories, including temperature and data sizes. Choose your units and precision, with calculations kept in your browser.
Works locally in your browser
How this tool works
Use this converter when two measurements describe the same physical dimension but use different units. Choose a category first so incompatible units cannot be mixed, then search by name, symbol, or familiar alias.
Inputs and definitions
- Measurement category limits both unit lists to one compatible dimension.
- Find a unit filters by names, symbols, and aliases while keeping your current selections available.
- Decimal places controls displayed rounding; calculations retain a higher-precision intermediate value.
Methodology
Each unit has a canonical scale within its category. The engine first converts the source value to that category's base unit, then converts the base value to the destination. Temperature uses an affine conversion that applies both an offset and a scale, rather than treating temperature like a simple ratio.
base value = (input + source offset) × source numerator ÷ source denominatorDigital data follows the standards' distinct meanings: a kilobyte is 1,000 bytes, while a kibibyte is 1,024 bytes. Exact decimal definitions are used for the supported customary units, including the international inch and pound and US liquid measures.
Assumptions
- Gallon, quart, cup, and fluid ounce entries use US liquid measures; they are labelled US in the unit list.
- Decimal data units use SI powers of 1,000 and binary IEC units use powers of 1,024.
- A displayed result is rounded to the selected decimal places, although the conversion path retains the unrounded decimal value.
Worked examples
Convert the freezing point from Celsius to Fahrenheit
Choose Temperature, enter 0, and convert from Celsius to Fahrenheit.
Convert Celsius to kelvin
Add 273.15, giving 273.15 kelvin as the canonical temperature.
Convert kelvin to Fahrenheit
Apply the Fahrenheit scale and offset to the canonical value.
0°C equals 32°F.
Compare a decimal megabyte with a binary mebibyte
Choose Digital data, enter 1, and convert from megabytes to mebibytes.
Convert the megabyte to bytes
The SI definition makes one megabyte exactly 1,000,000 bytes.
Divide by bytes per mebibyte
A mebibyte contains 1,048,576 bytes, so divide the byte value by that binary quantity.
1 MB is approximately 0.95367432 MiB when displayed to eight decimal places.
Limitations and common mistakes
The converter covers the units listed in the interface. It does not infer measurement uncertainty, significant figures, local trade conventions, density-based mass-volume relationships, or currency exchange rates.
Frequently asked questions
Why can I not convert between any two units?
A valid conversion requires the same dimension on both sides. A length can become another length, but it cannot become a mass without additional physical information.
What is the difference between MB and MiB?
A megabyte (MB) is 1,000,000 bytes under SI. A mebibyte (MiB) is 1,048,576 bytes under IEC. The converter keeps those units separate and labels them explicitly.
Why does temperature need a different formula?
Celsius, Fahrenheit, and kelvin do not share the same zero point. Converting them requires an offset as well as multiplication or division.
Does changing decimal places change the conversion?
It changes the displayed rounding only. The engine converts through the unrounded canonical value, which also supports accurate swap and round-trip behavior.
Sources
- Guide for the Use of the International System of Units (SI) — National Institute of Standards and Technology (accessed )
- Prefixes for binary multiples — International Electrotechnical Commission (accessed )
Method and content record
The method, examples and limitations describe how this tool works. Recorded checks do not establish independent professional review.
Record attribution, date and versions
Record attribution: ToolsOrigin calculation review; introduction guidance checked by Codex.
Record date: .
Content version 1.0.1. Engine version 1.0.0.