Length & Distance Converter

Convert between meters, kilometers, miles, feet, inches and more.

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Length & Distance
Metric ↔ Imperial ↔ Astronomical

Weight & Mass Converter

Convert between kilograms, pounds, ounces, stones, tonnes and more.

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Weight & Mass
Metric ↔ Imperial ↔ Avoirdupois
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Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin and Rankine instantly.

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Temperature
Celsius ↔ Fahrenheit ↔ Kelvin ↔ Rankine
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Digital Storage Converter

Convert between bits, bytes, KB, MB, GB, TB, PB and binary prefixes (KiB, MiB, GiB).

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Digital Storage
Decimal ↔ Binary (IEC) ↔ Bits
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Binary & Number Systems

Convert between Decimal, Binary, Hexadecimal and Octal number systems instantly.

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Binary & Number Systems
Decimal ↔ Binary ↔ Hex ↔ Octal
DEC
Decimal (Base 10)
BIN
Binary (Base 2)
HEX
Hexadecimal (Base 16)
OCT
Octal (Base 8)

Cooking & Recipe Converter

Convert cups, tablespoons, teaspoons, fluid ounces and milliliters. Plus grams, ounces and pounds for baking.

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Volume (Cups, tbsp, mL…)
US Cup ↔ Metric ↔ fl oz ↔ mL
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Weight (g, kg, oz, lb)
Grams ↔ Ounces ↔ Pounds ↔ Kilograms
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Free, Accurate Converters for Every Need

Five categories. 50+ unit types. All sourced from NIST and IEC standards.

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Length & Distance Converter

Convert between meters, kilometers, miles, feet, inches, centimeters, nautical miles, and more. The exact factor between feet and meters is 1 ft = 0.3048 m by international definition (1959). The mile is defined as exactly 1,609.344 meters. Our length converter supports 15+ units and updates in real time.

Common use cases: converting GPS distances when traveling between metric and imperial countries, verifying heights in meters vs feet, calculating race distances (5K = 3.107 miles, marathon = 42.195 km = 26.219 miles).

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Weight & Mass Converter

Convert between kilograms, pounds, ounces, grams, tonnes, stones, and more. The exact pound-to-kilogram factor is 1 lb = 0.45359237 kg — set by international agreement in 1959. The stone (UK) = 14 pounds = 6.35029 kg. Our weight converter handles 12+ units with 10 significant digits of precision.

Common use cases: converting body weight between lbs and kg for medical forms, calculating shipping weights, understanding product specifications that switch between metric and imperial.

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Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin, and Rankine. Key reference points: water freezes at 0°C = 32°F = 273.15 K; body temperature is 37°C = 98.6°F = 310.15 K; absolute zero is −273.15°C = −459.67°F = 0 K. Kelvin is the SI base unit used in all scientific calculations.

Common use cases: cooking and oven temperature conversion, interpreting weather forecasts when traveling, understanding colour temperature of light bulbs and displays (2700K warm white vs 5500K daylight).

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Digital Storage Converter

Convert between bits, bytes, KB, MB, GB, TB, PB and IEC binary prefixes (KiB, MiB, GiB, TiB). Important distinction: 1 GB = 1,000,000,000 bytes (decimal, used by drive manufacturers), while 1 GiB = 1,073,741,824 bytes (binary, used by operating systems). This is why a 1 TB hard drive shows ~931 GiB in Windows.

Common use cases: understanding why your hard drive shows less space than advertised, comparing cloud storage plans, calculating how many photos or videos fit in a given space.

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Binary & Number Systems Converter

Convert between decimal (base 10), binary (base 2), hexadecimal (base 16), and octal (base 8). All four representations of any integer are shown simultaneously. Hexadecimal is widely used in web colours (#FF5733), memory addresses, and colour profiles. Binary is the fundamental language of computing — every file is ultimately stored in 0s and 1s.

Common use cases: programming and computer science coursework, understanding Unix file permissions in octal (chmod 755), debugging hex colour codes in web design.

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The Smartest Way to Convert Units

Everything you need, nothing you don’t.

Instant Results

Conversions happen as you type — no button to press, no waiting. Pure speed.

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High Precision

Up to 10 significant digits of accuracy. Scientific notation for very large or small values.

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Dark & Light Mode

Switch between themes with one click. Your preference is saved automatically.

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Mobile Friendly

Works perfectly on phones and tablets. Convert on the go, anywhere.

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No Account Needed

No sign-up, no email, no tracking. Just open and convert.

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Always Free

Every converter on this site is free and always will be.

Frequently Asked Questions

Common questions about unit conversions and how our converters work.

How many kilometers are in a mile?

The exact conversion factor is 1 mile = 1.609344 kilometers, a value fixed by the International Yard and Pound Agreement of 1959. Conversely, 1 km = 0.621371 miles. Practical examples: a marathon is 42.195 km (26.219 miles), a 5K race equals 3.107 miles, and a 60 mph speed limit equals 96.56 km/h. Note that a nautical mile is different — it equals 1.852 km and is used in aviation and maritime navigation, not on land.

How do you convert Celsius to Fahrenheit?

To convert Celsius to Fahrenheit use °F = (°C × 9/5) + 32; to reverse, °C = (°F − 32) × 5/9. Key reference points: 0°C = 32°F (water freezes), 100°C = 212°F (water boils), 37°C = 98.6°F (normal body temperature), and −40° is identical in both scales. For quick mental math, double the Celsius value and add 30 — this lands within ±2°F for most everyday temperatures.

What is the difference between GB and GiB?

A gigabyte (GB) equals exactly 1,000,000,000 bytes (10⁹, decimal). A gibibyte (GiB) equals 1,073,741,824 bytes (2³⁰, binary). Hard drive manufacturers advertise in decimal GB because the numbers look larger, while operating systems like Windows report in binary GiB — that's why a "1 TB" drive shows only ~931 GiB. The IEC 80000-13 standard introduced the GiB prefix in 1998 to eliminate this confusion. Our Digital Storage Converter handles both systems automatically.

How do you convert pounds to kilograms?

The exact conversion factor is 1 pound = 0.45359237 kilograms, fixed by the 1959 International Yard and Pound Agreement. Practical examples: a 150 lb person weighs 68.04 kg, the standard airline carry-on limit of 23 kg equals 50.7 lbs, and a pound of cheese is 453.6 g. In the UK, body weight is often given in stones (1 stone = 14 lbs = 6.35 kg). Our Weight Converter handles kilograms, grams, pounds, ounces, stones, and metric tonnes.

How do you convert a decimal number to binary?

Repeatedly divide the number by 2, recording the remainder (0 or 1) at each step, then read the remainders from bottom to top. Example: 42 ÷ 2 = 21 r0, 21 ÷ 2 = 10 r1, 10 ÷ 2 = 5 r0, 5 ÷ 2 = 2 r1, 2 ÷ 2 = 1 r0, 1 ÷ 2 = 0 r1 → 42 = 101010 in binary. Binary exists because digital circuits have two states (on/off). Each binary digit is a "bit," and 8 bits form a byte. Hexadecimal (base-16) is a compact shorthand — each hex digit represents exactly 4 bits.

How many centimeters are in an inch?

Exactly 2.54 centimeters are in one inch — this conversion is exact by international definition since 1959. To convert inches to cm, multiply by 2.54. To go the other way, divide by 2.54 (or multiply by 0.3937). For example: 12 inches = 30.48 cm; 1 meter = 39.3701 inches.

How do I convert Fahrenheit to Celsius?

Subtract 32, then multiply by 5/9. Formula: °C = (°F − 32) × 5/9. Common examples: 32°F = 0°C, 98.6°F = 37°C (body temp), 212°F = 100°C, 350°F = 176.7°C (baking temp). Our temperature converter handles all four scales — Celsius, Fahrenheit, Kelvin, and Rankine.

What is absolute zero in Celsius and Fahrenheit?

Absolute zero — the coldest theoretically possible temperature — is 0 K = −273.15°C = −459.67°F. At this temperature, all molecular motion ceases. It can be approached but never fully reached in practice. The Kelvin scale starts at absolute zero, making it essential for physics, chemistry, and engineering calculations.

How many ounces are in a kilogram?

One kilogram equals 35.274 ounces (avoirdupois). Conversely, one ounce equals approximately 28.3495 grams. Note that "ounce" in cooking can also mean fluid ounce (volume), which is different — a fluid ounce is approximately 29.57 mL. Our weight converter handles kilograms, pounds, ounces, grams, stones, and tonnes.

What is the difference between a megabyte and a mebibyte?

A megabyte (MB) = 1,000,000 bytes in the decimal (SI) system. A mebibyte (MiB) = 1,048,576 bytes in the binary (IEC) system. The difference is about 4.86%. Operating systems like Windows and macOS often report file sizes in binary units (MiB) but label them as "MB," which causes confusion. Our digital storage converter lets you switch between decimal and binary prefixes clearly.

What is hexadecimal used for?

Hexadecimal (base 16) is used extensively in computing as a compact way to represent binary data. Common uses: web colours (#RRGGBB format), memory addresses, MAC addresses, IPv6 addresses, byte-level debugging, and cryptographic hashes. Each hex digit represents exactly 4 binary digits (bits), so 2 hex digits = 1 byte. For example, #FF = 255 decimal = 11111111 binary.

How many feet are in a meter?

One meter equals exactly 3.28084 feet, or equivalently 3 feet and 3.37 inches. The foot is defined as exactly 0.3048 meters. Common reference: a standard doorway is about 2 meters (6.56 ft) tall; an NBA basketball player at 6 ft 6 in is about 1.98 meters tall. Our length converter handles all combinations of feet, inches, meters, and centimeters.

Does SwiftConvertHub store my data?

No. SwiftConvertHub performs all conversions client-side in your browser. No values you enter are transmitted to a server or stored anywhere. Your conversion history is not logged. The only data we collect is standard anonymous analytics (page views, country, device type) via Google Analytics — no personally identifiable information is collected or stored.

How accurate are SwiftConvertHub's converters?

Our converters use conversion factors sourced from NIST Handbook 44, the SI Brochure (9th edition), and IEC 80000-13 for digital storage. Results are accurate to 10 or more significant digits. For safety-critical, engineering, or scientific applications, always verify with a calibrated instrument. See our accuracy disclaimer for full details.

What countries use the metric system?

The metric system (SI) is the official measurement system in every country except the United States, Liberia, and Myanmar. The UK officially uses metric but retains miles for road distances and pints for draught beer. Canada uses metric but miles per hour appear on older infrastructure. Most scientific, medical, and engineering work worldwide uses metric regardless of the country's official system.