Length Converter
1 Meter = 3.28084 Feet
The most complete free unit converter online — convert length, weight, temperature, volume, area, speed, data, pressure, and energy instantly. Whether you need a metric converter for science and school, a measurement converter for cooking and construction, or a quick online unit converter for travel and engineering, every conversion you need is right here in one place.
A unit converter is a tool that translates a value from one unit of measurement into an equivalent value in a different unit — instantly and accurately. Rather than applying conversion formulas by hand, a unit converter calculator does the arithmetic for you in milliseconds, removing the risk of human error and saving time in every discipline where measurement matters.
Measurement conversion is one of the most common everyday calculations in the world. A traveller landing in the United States needs to convert kilometres to miles on road signs. A nurse needs to convert a patient's weight from pounds to kilograms before calculating a medication dose. A chef following a British recipe needs to convert millilitres to cups. An engineer receiving specifications from a US client needs to convert inches to centimetres before fabrication. In every one of these situations, an accurate online unit converter is the fastest and safest solution.
What makes this tool different from a basic multiplication table is scope and precision. Our measurement converter covers 10 major categories — length, weight, temperature, volume, area, speed, time, data, pressure, and energy — and handles the full range of units within each category. Temperature conversions, for example, are not simple multiplications: Fahrenheit to Celsius requires subtracting 32 before scaling, and Kelvin starts at absolute zero. This tool manages all of that complexity with a single click.
The International System of Units is the global standard — built on powers of 10, making conversions fast and logical.
A collection of traditional units still common in the United States, and partially in the UK. Conversion factors vary and must be memorized.
The International System of Units (SI) is the global standard for measurement, adopted by 195 countries and used universally in science, medicine, and international trade. The metric converter system is built entirely on powers of 10, which makes scaling between units logical and fast — you simply move the decimal point. 1 kilometre is exactly 1,000 metres. 1 kilogram is exactly 1,000 grams. No memorisation of irregular conversion factors required.
| Base Unit | Measures | Symbol |
|---|---|---|
| Meter | Length / Distance | m |
| Kilogram | Mass / Weight | kg |
| Second | Time | s |
| Kelvin | Temperature | K |
| Liter | Volume (non-SI accepted) | L |
| Ampere | Electric current | A |
| Candela | Luminous intensity | cd |
Used by: 195+ countries worldwide, all scientific and medical fields globally.
The imperial system is a collection of units that evolved from historical English standards. Unlike the metric system, its conversion factors are irregular and must be memorised — 12 inches in a foot, 3 feet in a yard, 1,760 yards in a mile, 16 ounces in a pound. The US uses its own variation called US Customary, which differs from British Imperial in some units. This is why a unit converter calculator is so valuable when working between the two systems.
| Unit | Measures | Metric Equivalent |
|---|---|---|
| Inch / Foot / Mile | Length | 2.54 cm / 30.48 cm / 1.609 km |
| Pound (lb) | Weight | 0.4536 kg |
| Fahrenheit (°F) | Temperature | (°F − 32) × 5/9 = °C |
| US Gallon | Volume | 3.785 L |
| Fluid Ounce (US) | Volume | 29.57 mL |
| Acre | Area | 4,047 m² |
| mph | Speed | 1.609 km/h |
Used by: United States (customary), Liberia, Myanmar (imperial). UK uses a mix in daily life.
Click the category tab at the top of the unit converter — Length, Weight, Temperature, Volume, Area, Speed, Time, Data, Pressure, or Energy. Each tab loads the correct set of units for that measurement type. If you need a length converter, click Length. If you need a weight converter, click Weight. The active tab highlights so you always know which category you are in.
Use the two dropdown menus to select your source unit and your target unit. For example, if you want to convert kilograms to pounds, set “From” to Kilograms and “To” to Pounds. The online unit converter supports dozens of units per category — including less common units like stones, nautical miles, knots, pascals, BTUs, and kibibytes — so specialist users are fully covered too.
Type your number into the input field. The result updates instantly — no need to press a button. The measurement converter also displays a quick conversion table below the result, showing a range of values for that unit pair so you can see the surrounding context at a glance. This is especially useful when planning a recipe, comparing specifications, or checking a range of sizes.
Click the Copy Result button to copy the converted value to your clipboard instantly. Paste it directly into a spreadsheet, document, message, or report. No need to manually write down or retype the number. This makes the unit converter calculator a fast, frictionless step in any professional or personal workflow — from payroll and invoicing to lab reports and engineering specs.
Engineers and builders use a measurement converter daily when working with international specifications. A US architect receiving blueprints in metric needs to convert metres to feet and inches before cutting materials. A civil engineer calculating load-bearing capacity needs to convert kilonewtons to pound-force. Even ordering hardware requires converting between metric and imperial bolt sizes to avoid costly mistakes on site.
All scientific measurement is conducted in SI units, but published data often comes from older studies using CGS units or from US labs using customary units. Researchers use a metric converter to translate results between systems before comparison or meta-analysis. Temperature conversion is particularly critical in chemistry and biology — a 1°C error in an incubation temperature can invalidate an experiment.
Recipes from the UK use grams and millilitres. Recipes from the US use cups, tablespoons, and fluid ounces. A weight converter and volume converter eliminates the guesswork when following international recipes. Professional chefs and serious home bakers rely on accurate conversions — a 20% error in flour weight changes the entire texture of a bread or cake.
Travellers constantly need a unit converter calculator when moving between countries. Speed limits change from mph to km/h. Temperatures switch between Celsius and Fahrenheit. Fuel is priced per litre in most countries but per gallon in the US. Aviation uses nautical miles and knots — completely different from road measurements. Our online unit converter covers all of these scenarios instantly.
Medication dosing in paediatrics and critical care is calculated in mg per kg of body weight. Nurses and pharmacists use a weight converter to convert a patient’s weight from pounds to kilograms. Blood pressure, glucose levels, and cholesterol values also use different units in different countries — mmHg vs kPa, mmol/L vs mg/dL. Accurate conversion is a clinical safety requirement.
Developers, IT administrators, and data engineers use a data storage unit converter to interpret storage specifications, transfer speeds, and memory requirements. Buying a 1 TB SSD, calculating whether a 5 Mbps connection can stream 4K video, or sizing a cloud storage bucket all require data unit conversion. Our tool handles bytes through petabytes and their binary equivalents (KiB, MiB, GiB, TiB).
| Prefix | Symbol | Factor | Decimal | Example |
|---|---|---|---|---|
| Tera | T | 10¹² | 1,000,000,000,000 | Terabyte (TB) |
| Giga | G | 10⁹ | 1,000,000,000 | Gigawatt (GW) |
| Mega | M | 10⁶ | 1,000,000 | Megabyte (MB) |
| Kilo | k | 10³ | 1,000 | Kilometer (km) |
| Hecto | h | 10² | 100 | Hectare (ha) |
| Deca | da | 10¹ | 10 | Decagram (dag) |
| (base) | — | 10⁰ | 1 | Meter, Gram, Liter |
| Deci | d | 10⁻¹ | 0.1 | Deciliter (dL) |
| Centi | c | 10⁻² | 0.01 | Centimeter (cm) |
| Milli | m | 10⁻³ | 0.001 | Millimeter (mm) |
| Micro | μ | 10⁻⁶ | 0.000001 | Micrometer (μm) |
| Nano | n | 10⁻⁹ | 0.000000001 | Nanosecond (ns) |
The length converter handles distance and dimension measurement across all common systems. Convert between millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, and nautical miles. The most searched conversion in this category is centimetres to inches, followed by inches to centimetres and miles to kilometres.
The weight converter covers mass and weight units for personal, commercial, and scientific use. Convert between milligrams, grams, kilograms, metric tonnes, ounces, pounds, stones, and US tons. Weight conversion is critical in healthcare, fitness, and international shipping. The most searched is kilograms to pounds — driven by fitness tracking and medical use.
The temperature converter is one of the most nuanced converters because temperature scales have different zero points and scaling factors. Convert between Celsius (most countries), Fahrenheit (US), and Kelvin (SI absolute scale used in science). Celsius to Fahrenheit is one of the top 10 most searched conversion queries globally, driven by weather, cooking, and travel.
Convert liquid and dry volume measurements across metric and imperial systems. Supported units include millilitres, litres, cubic metres, US fluid ounces, US cups, US pints, US quarts, US gallons, UK gallons, and UK pints. Note that US and UK volume units differ significantly — a US cup is 236.6 mL while a UK cup is 250 mL.
Convert area measurements for real estate, land surveying, architecture, and agriculture. Supported units include square millimetres through square kilometres, square inches through square miles, hectares, and acres. Real estate listings in the US use square feet while the rest of the world uses square metres. Land area in farming uses acres in the US/UK and hectares everywhere else.
Convert velocity and speed between metres per second, kilometres per hour, miles per hour, knots, and Mach. Speed conversion is used in automotive, aviation, maritime, athletics, and meteorology. Mach conversion is relevant in aerospace engineering and supersonic aircraft specifications. Aviation uses nautical miles and knots — a standard completely separate from road speed measurements.
Multiply miles by 1.6, or simply add 60% to your figure. A quick way to remember it in traffic: 60 mph works out to roughly 100 km/h.
Double the °C value, subtract 10%, then add 32. Or remember: 16°C = 61°F — the digits just swap! Great for quick weather checks abroad.
Divide pounds by 2.2. For a rough estimate, just halve the number — 2 lbs is about 1 kg. Useful for reading gym equipment in different countries.
Multiply by 0.3 for a quick ballpark. 10 feet is approximately 3 metres. Handy for reading ceiling heights or room dimensions in property listings.
Divide litres by 4 for a rough US gallon figure. 4 litres is close to 1 gallon. Useful when comparing fuel prices across countries.
Multiply inches by 2.5 for a quick estimate. 4 inches is about 10 cm. Great for reading screen sizes, paper sizes, and clothing measurements.
A unit converter is a tool that transforms a numerical value from one unit of measurement to an equivalent value in a different unit. It works by applying a conversion factor — a fixed mathematical ratio between two units. For example, 1 inch equals exactly 2.54 centimetres, so converting 5 inches to centimetres means multiplying by 2.54 to get 12.7 cm. Our unit converter calculator stores all conversion factors internally and applies the correct formula instantly, so you never need to remember the ratios yourself.
The metric converter system (officially called SI — Système International d’Unités) is built on multiples of 10, making it straightforward to scale: 1 kilometre is 1,000 metres, 1 kilogram is 1,000 grams, 1 litre is 1,000 millilitres. The imperial system uses irregular conversion factors that must be memorised: 1 foot is 12 inches, 1 yard is 3 feet, 1 mile is 5,280 feet, and 1 pound is 16 ounces. The metric system is used by 195+ countries and all scientific fields. The US primarily uses customary units (a variation of imperial) for everyday measurements, while science, medicine, and manufacturing even in the US operate in metric.
To convert centimetres to inches, divide the centimetre value by 2.54 (since 1 inch equals exactly 2.54 cm). For example, 30 cm ÷ 2.54 = 11.81 inches. To convert the other way — inches to centimetres — multiply the inch value by 2.54. For example, 6 inches × 2.54 = 15.24 cm. Use the length converter above to do this instantly for any value — just select Centimetres and Inches from the dropdowns in the Length tab.
To convert kilograms to pounds, multiply the kg value by 2.20462 (since 1 kg equals approximately 2.205 lbs). For example, 70 kg × 2.20462 = 154.32 lbs. To convert pounds back to kilograms, divide by 2.20462 — or multiply by 0.4536. For a quick mental estimate, divide the kg value by 0.45 or multiply by 2.2. Use the weight converter tab above for precise results with any weight value in any unit combination.
The formula to convert Celsius to Fahrenheit is: °F = (°C × 9/5) + 32. For example, 25°C × 1.8 + 32 = 77°F. To convert Fahrenheit to Celsius, the formula reverses to: °C = (°F − 32) × 5/9. For example, 98.6°F − 32 = 66.6, then × 5/9 = 37°C (normal human body temperature). A quick mental trick: 16°C = 61°F (the digits swap), and every 5°C change equals a 9°F change. Use the temperature converter tab above for any temperature conversion without needing to apply the formula manually.
A US gallon equals 3.785 litres, while a UK (imperial) gallon equals 4.546 litres — making the UK gallon approximately 20% larger. This difference also affects pints and fluid ounces: a US pint is 473 mL while a UK pint is 568 mL. Fuel economy figures (miles per gallon) will differ significantly depending on which gallon is used, so always check the source when comparing car fuel efficiency across US and UK vehicles. Use the Volume tab in our online unit converter to convert between US and UK volume units precisely.
Technically, the SI (metric) standard defines 1 KB (kilobyte) as exactly 1,000 bytes. However, the computing industry has historically used 1 KB to mean 1,024 bytes (2¹⁰), which is why the IEC introduced the kibibyte (KiB) — 1 KiB = 1,024 bytes — to eliminate ambiguity. In practice, most operating systems (Windows, macOS, Linux) still display file sizes using 1 KB = 1,024 bytes. Storage manufacturers typically use 1 KB = 1,000 bytes, which is why a “500 GB” hard drive shows as ~465 GB on your computer. Our data storage unit converter supports both binary (KiB, MiB, GiB) and decimal (KB, MB, GB) units.
The persistence of imperial units in the US comes down to history, inertia, and cost. When the US was founded, British imperial units were standard. While science and medicine switched to metric in the 20th century, everyday consumer life — road signs, weather forecasts, cooking recipes, clothing sizes, and construction — remained imperial because changing would require updating tens of millions of signs, products, regulations, and consumer expectations simultaneously. The cost and disruption of that transition has consistently outweighed the benefit. Congress passed the Metric Conversion Act in 1975 making metric the preferred system, but the conversion was voluntary and largely didn’t happen in daily life. Our measurement converter exists precisely because this dual-system reality creates a constant need for conversion.
A nautical mile equals 1.852 kilometres (approximately 1.151 statute miles), and it is defined as one minute of arc of latitude along any meridian of the Earth’s surface. This means the nautical mile is directly tied to the Earth’s geometry, making it ideal for navigation — a chart position that is 1 degree of latitude from another point is exactly 60 nautical miles away. A knot (the unit of speed in maritime and aviation) equals one nautical mile per hour. This geographic definition is why nautical miles are used in shipping, aviation, and meteorology. Use the length converter tab in our unit converter to convert nautical miles to kilometres, metres, or statute miles.
Yes, this online unit converter is completely free with no registration, login, or subscription required. All calculations happen instantly in your browser — no data is sent to a server, and your input values are never stored or shared. The tool works on all devices including mobile phones, tablets, and desktop computers. There are no limits on the number of conversions you can run, and no features are locked behind a paywall. SmartCalculatorTool is committed to providing accurate, free tools for everyday use.