Convert length, weight, temperature, volume, area, speed, time and data storage instantly. See your value converted to every unit at once. Free, accurate, no signup.
Unit conversion comes up constantly — comparing a recipe in cups to grams, checking if your luggage is under the airline's kilogram limit, converting a US job salary's mileage reimbursement to your local currency's distance unit, or figuring out why your "1 TB" hard drive shows less space than advertised. Most converters online cover three or four basic categories. This tool covers eight: Length, Weight/Mass, Temperature, Volume, Area, Speed, Time, and Data Storage — over 60 individual units in total.
Every category includes both metric (SI) and imperial/US customary units, so you can convert in either direction. The "All Units at Once" table updates live as you type, showing your value converted to every unit in the category simultaneously — handy when you're not sure exactly which unit you need, or when you want to sanity-check a conversion against a familiar unit.
The metric system (now formalized as the International System of Units, or SI) was developed in France in the 1790s, designed around powers of 10 for simplicity — 1 kilometer = 1,000 meters, 1 kilogram = 1,000 grams. It's used as the primary system in nearly every country in the world.
The imperial system, and its close relative the US customary system, evolved from older English units of measurement — feet, inches, pounds, gallons — many of which trace back centuries and were based on practical references (a foot was literally based on human foot length in some historical versions). The United States continues to use US customary units for most everyday purposes, while the UK officially uses metric but retains imperial units in common speech (miles for road distances, pints for beer, stone for body weight).
This mix is why unit conversion remains a daily necessity — international business, travel, cooking, engineering, science, and even casual conversations between people from different countries regularly require converting between these two systems.
The most frequently searched conversions, calculated to 4 decimal places. Use these as quick reference, or use the converter above for any custom value.
| Conversion | Result | Formula / Factor |
|---|---|---|
| 1 kilometer | 0.6214 miles | km × 0.621371 |
| 1 mile | 1.6093 km | mi × 1.609344 |
| 1 meter | 3.2808 feet | m × 3.28084 |
| 1 inch | 2.54 cm | in × 2.54 |
| 1 kilogram | 2.2046 lbs | kg × 2.20462 |
| 1 pound | 0.4536 kg | lb × 0.453592 |
| 0°C | 32°F | (°C × 9/5) + 32 |
| 100°C | 212°F | (°C × 9/5) + 32 |
| 1 liter | 0.2642 US gal | L × 0.264172 |
| 1 US gallon | 3.7854 liters | gal × 3.78541 |
| 1 square meter | 10.7639 sq ft | m² × 10.7639 |
| 1 acre | 4,046.86 m² | acre × 4046.8564 |
| 60 mph | 96.5606 km/h | mph × 1.609344 |
| 1 GB (decimal) | 0.9313 GiB | GB ÷ 1.073742 |
Recipe conversions trip people up more than almost any other unit conversion — especially when following recipes from a different country. Here's the reference you need for kitchen measurements.
| US Measurement | Metric Equivalent | Other US Equivalents |
|---|---|---|
| 1 teaspoon (tsp) | 4.93 mL | 1/3 tablespoon |
| 1 tablespoon (tbsp) | 14.79 mL | 3 teaspoons |
| 1 fluid ounce (fl oz) | 29.57 mL | 2 tablespoons |
| 1 cup | 236.59 mL | 16 tbsp · 8 fl oz · 48 tsp |
| 1 pint | 473.18 mL | 2 cups · 16 fl oz |
| 1 quart | 946.35 mL | 2 pints · 4 cups |
| 1 US gallon | 3.785 L | 4 quarts · 16 cups |
⚠️ US vs UK measurements: A US cup (236.6 mL) is different from a "metric cup" used in Australia and the UK (250 mL). UK recipes that use "pints" or "gallons" usually mean Imperial measurements, which are about 20% larger than US measurements for the same unit name. Always check which system a recipe uses before converting — when in doubt, look for the metric (mL/g) measurement if provided, as it's unambiguous.
This is one of the most common sources of confusion in computing — and it's caused by two competing definitions of the same prefixes.
| Unit | Definition | Bytes | Used By |
|---|---|---|---|
| KB (kilobyte) | Decimal (SI) | 1,000 | Storage manufacturers, file sizes on macOS |
| KiB (kibibyte) | Binary (IEC) | 1,024 | Memory (RAM), correct technical term |
| MB (megabyte) | Decimal (SI) | 1,000,000 | Storage manufacturers |
| MiB (mebibyte) | Binary (IEC) | 1,048,576 | RAM, correct technical term |
| GB (gigabyte) | Decimal (SI) | 1,000,000,000 | Storage manufacturers |
| GiB (gibibyte) | Binary (IEC) | 1,073,741,824 | RAM, correct technical term |
| TB (terabyte) | Decimal (SI) | 1×10¹² | Storage manufacturers |
| TiB (tebibyte) | Binary (IEC) | 1.0995×10¹² | RAM, correct technical term |
Storage manufacturers advertise drives using the decimal definition — a "1 TB" drive contains 1,000,000,000,000 bytes. But Windows displays storage using binary math while still labeling it "GB" — so that same drive shows as roughly 931 "GB" (which is actually GiB) in Windows. The drive isn't smaller than advertised — it's a labeling inconsistency between the storage industry (decimal) and operating systems (binary, mislabeled).
💡 Quick way to remember: If you see "-ibi" in the name (kibi, mebi, gibi, tebi), it's binary (×1024). If it's just "kilo, mega, giga, tera", it's technically decimal (×1000) — even though many programs mislabel binary values this way. Use the Data Storage tab above to convert between both systems instantly.
Unlike most units, temperature scales don't share a common zero point — so conversions require formulas, not simple multiplication.
Kelvin is the SI base unit for temperature and has no negative values — 0 K ("absolute zero") is the coldest possible temperature, equal to -273.15°C or -459.67°F. Kelvin is used in scientific and engineering contexts. Celsius is used for everyday temperatures in most of the world. Fahrenheit is primarily used in the United States.
Select a category from the tabs at the top — Length, Weight, Temperature, Volume, Area, Speed, Time, or Data Storage. Enter your value, choose your "From" and "To" units, and the result updates instantly. Use the swap button (⇄) to quickly reverse the conversion direction.
The "All Units at Once" table below the converter shows your input value converted to every unit in the selected category simultaneously — useful when you're not sure which unit you need, or when you want to compare multiple representations of the same measurement at a glance.
All conversion factors used are based on internationally recognized standards from the International Bureau of Weights and Measures (BIPM) and NIST. Results are displayed with appropriate precision for the magnitude of the number — small numbers show more decimal places, large numbers are rounded sensibly. All calculations happen in your browser — nothing is sent to a server.
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