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Convert any unit or currency instantly — all in one clean tool.
Quick Reference
The converter above is free forever: 15 categories, 100+ units, 30 currencies with editable rates, live two-way conversion, copy & shareable links, and precision control. Pro adds the extras professionals ask for:
Want to try first? Use demo code AV-UNIT-CONVERTER-DEMO to preview every Pro feature on this device.
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Whether you're converting kilometers to miles for a road trip, grams to ounces for a recipe, or Celsius to Fahrenheit for a weather check, switching between measurement systems is a daily friction point for millions of people. Our unit converter handles eight distinct categories — length, mass, temperature, volume, area, speed, digital storage, and time — all in one place, without switching tools.
Each conversion uses precise mathematical factors based on the International System of Units (SI). Length conversions are anchored to the meter: one kilometer is exactly 1,000 meters, one inch is exactly 0.0254 meters, one mile is exactly 1,609.344 meters. Mass conversions are anchored to the kilogram: one pound is exactly 0.45359237 kilograms, one ounce is exactly 28.349523125 grams.
Temperature conversions use the correct affine formula rather than a simple multiplication, so -40 degrees Celsius equals -40 degrees Fahrenheit, and the freezing point stays fixed at 0 degrees Celsius regardless of how many times you convert back and forth. The converter also supports Kelvin (used in science and engineering) and Rankine (used in some US engineering contexts).
Live currency APIs require server infrastructure. To keep this tool fully client-side and always available offline, we embed approximate mid-market rates for 30 major currencies, labeled with their reference date. If you're doing serious financial planning, tap "Edit Rates" and type in the current rate from your bank or Google Finance — your edits are saved locally in your browser and override the defaults until you reset them.
The currency panel covers the US Dollar, Euro, British Pound, Japanese Yen, Canadian Dollar, Australian Dollar, Swiss Franc, Chinese Yuan, Indian Rupee, Mexican Peso, Brazilian Real, South Korean Won, Singapore Dollar, Hong Kong Dollar, and 16 more frequently traded currencies including the Norwegian Krone, Swedish Krona, Turkish Lira, Saudi Riyal, UAE Dirham, Thai Baht, Malaysian Ringgit, Indonesian Rupiah, Philippine Peso, Pakistani Rupee, Vietnamese Dong, Polish Zloty, and Czech Koruna.
All currency conversion works through a USD base: your input amount is converted to USD first, then from USD to the target currency. This means any pair of the 30 currencies can be converted without storing 870 separate exchange rates — just 30 rates relative to USD.
Both input fields update live as you type. Change the value on either side and the other recalculates immediately. Hit the swap button and the units flip — no need to re-enter the number. The formula used is shown below the fields so you always understand exactly what calculation is happening. The quick reference table below the main converter shows eight common output values simultaneously, so you can see how your input compares across the full range of units without clicking through each one individually.
The Data category includes both binary and decimal storage units. Kilobytes (KB) in the SI standard equal 1,000 bytes, while kibibytes (KiB) equal 1,024 bytes. This difference compounds at larger scales: a "gigabyte" as reported by your operating system is typically 1,073,741,824 bytes (GiB), while a hard drive manufacturer labels 1,000,000,000 bytes as a gigabyte (GB). Our converter includes both variants so you can accurately translate what your OS reports versus what a drive's advertised capacity means.
The Time category converts between milliseconds, seconds, minutes, hours, days, weeks, months, and years. The month value uses the average Gregorian month of 30.44 days, and the year uses 365.25 days to account for leap years. These are the standard values used in most scientific and engineering contexts. For calendar-exact date arithmetic (counting specific days between specific dates), use a dedicated date calculator instead.
Beyond everyday length, mass and temperature conversions, this tool now covers the categories engineers, students, drivers and DIYers reach for most: pressure (psi, bar, kPa, atmospheres, mmHg and inHg for tires, weather and diving), energy (joules, calories, kilowatt-hours and BTU for nutrition, fitness and utility bills), power (watts, kilowatts and both mechanical and metric horsepower), frequency (Hz through GHz plus RPM) and angle (degrees, radians, gradians and arcminutes).
The Fuel Economy category is built for a global audience: enter a US MPG figure and instantly read it as L/100 km, Imperial (UK) MPG or kilometers per liter. Because economy is a reciprocal scale, simple multiplication gives the wrong answer — this converter routes everything through L/100 km so a thirsty 15 MPG truck and an efficient 3 L/100 km hybrid both convert accurately. It is the fastest way to compare a spec sheet written for one market against the units you actually think in.
Every conversion can be copied as clean text with one tap, or turned into a shareable link that reopens the exact category, units and value on any device — handy for sending a measurement to a colleague or bookmarking a go-to conversion. A decimals control switches between automatic significant figures and a fixed 0, 2, 4 or 6 decimal places when you need consistent rounding for a report or invoice. Power users can unlock pinned favorites, a conversion history, batch conversion and CSV/TXT export.
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