Conversion calculators
Length, weight, temperature, and live currency — converted instantly, with the exact formula shown for every unit pair. The currency tool pulls a real-time exchange rate on each calculation; every other conversion runs entirely offline in your browser.
Length unit converter
Convert between metric and imperial length units.
How this calculator works
Every length unit here is first converted to a common base unit (meters), then converted from meters into the target unit. This two-step approach means adding a new unit only requires knowing its relationship to meters, rather than a separate formula for every possible pair.
Result = (value × factor to meters) / (factor to meters of target unit)
The metric system (meters, kilometers, centimeters) is used almost universally for measurement and science, while imperial units (miles, yards, feet, inches) remain standard for everyday use in the United States — which is why unit conversion between the two systems comes up so often.
Weight / mass converter
Convert between common weight and mass units.
How this calculator works
Like the length converter, every weight unit is converted through a common base (kilograms) so any unit can convert to any other using just its own conversion factor.
Result = (value × factor to kg) / (factor to kg of target unit)
Note the distinction between mass and weight: kilograms and pounds-mass measure the amount of matter in an object (which stays constant), while "weight" in physics technically refers to the force of gravity on that mass — though in everyday conversion, the two terms are used interchangeably.
Temperature converter
Convert between Celsius, Fahrenheit, and Kelvin.
How this calculator works
Unlike length and weight, temperature scales don't share a common zero point, so conversions use addition/subtraction alongside multiplication rather than a single shared factor. Celsius and Kelvin share the same size of degree, just offset by 273.15; Fahrenheit uses a different-sized degree entirely.
°F = (°C × 9/5) + 32
K = °C + 273.15
°C = (°F − 32) × 5/9
0 K (absolute zero, about −273.15°C or −459.67°F) is the theoretical point at which all molecular motion stops — it's why Kelvin has no negative values, unlike Celsius and Fahrenheit.
Currency converter
Live exchange rates, updated daily from the European Central Bank.
Rates are fetched live from a public exchange rate service and may not reflect real-time market or bank rates exactly.
How this calculator works
Currency conversion multiplies your amount by the current exchange rate between the two currencies — how many units of the target currency one unit of the source currency can buy right now. Unlike length or weight, these rates change continuously based on global markets, so this tool fetches current rates rather than using fixed constants.
Converted amount = amount × exchange rate (source currency → target currency)
The rate you see here is the mid-market rate (the midpoint between buy and sell prices on the global market). Banks and money transfer services typically add a margin on top of this rate plus a fee, so the amount you actually receive when exchanging cash is usually somewhat less than a pure mid-market calculation suggests.
Frequently asked questions
Why does the currency converter show a different rate than my bank?
This tool shows the mid-market exchange rate — the raw rate at which currencies trade globally. Banks and exchange services typically add a margin (sometimes 2–5%) on top of this rate, plus possible fees, so the rate you're offered when actually exchanging money is usually less favorable than the mid-market figure shown here.
How often are the currency exchange rates updated?
Rates are refreshed roughly once per day from a public exchange rate feed, not in real time. For time-sensitive transactions involving significant amounts, always confirm the live rate directly with your bank or exchange provider before proceeding.
Why is there no single "correct" temperature conversion formula?
There is one correct formula per direction (C→F, F→C, C→K), but people often mix up the order of operations — multiplying by 9/5 before adding 32 versus after gives very different, wrong results. This calculator applies the formulas in the correct order automatically.
What's the difference between a metric ton and a US ("short") ton?
A metric ton (tonne) equals exactly 1,000 kg. A US short ton, common in the United States, equals 2,000 pounds — roughly 907 kg, about 9% lighter than a metric ton. This calculator uses the metric ton; always double check which "ton" a source is referring to, since the two are easy to confuse.
Why do some countries use different decimal and thousands separators?
Many countries write large numbers with a period as the thousands separator and a comma as the decimal point (e.g. 1.234,56), the reverse of US/UK convention (1,234.56). This doesn't change any of the underlying conversion math, but it's worth noting if you're cross-checking results against sources from different regions.
Are these conversion factors exact or rounded?
Most length and weight conversions used here (like 1 inch = 2.54 cm, or 1 pound = 0.453592 kg) are internationally defined exact values, not approximations — so results are limited only by floating-point display precision, not by the accuracy of the conversion factor itself.