Conversion Calculator | Be More Peter

Be More Peter

Conversion calculator

Length · weight · temperature · volume · area · speed · and more

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A single calculator covering every everyday conversion - length, weight, temperature, volume, area, speed, data, time, pressure and energy. Type a value in either field and the result updates instantly. Switch units in either direction. Use the swap button to reverse the conversion without retyping.

No sign-up, no ads, no limit on how many times you use it.

How to use this calculator

Select a category using the buttons at the top - Length, Weight, Temperature, Volume, and so on. The unit dropdowns update automatically for the category you choose.

Type your value in the left field. The converted result appears immediately in the right field. You can also type in the right field and convert in the opposite direction - both fields work as inputs.

Swap the units using the ⇄ button between the two fields. This reverses the from and to units without clearing your value - useful for checking the conversion both ways.

Change the units using the dropdowns below each field. The result updates automatically when you change either unit.

What each category covers

Length - millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, nautical miles and light years.

Weight - milligrams, grams, kilograms, metric tonnes, ounces, pounds, stones and imperial tonnes.

Temperature - Celsius, Fahrenheit and Kelvin. The formula used for each conversion is shown in the result panel.

Volume - millilitres, centilitres, litres, cubic metres, and both UK and US variants of teaspoons, tablespoons, fluid ounces, pints, gallons and cups.

Area - square millimetres, centimetres, metres, kilometres, inches, feet, yards, acres, hectares and square miles.

Speed - metres per second, kilometres per hour, miles per hour, knots, feet per second and the speed of light.

Data - bits, bytes, kilobytes, megabytes, gigabytes and terabytes.

Time - milliseconds, seconds, minutes, hours, days, weeks, months and years.

Pressure - pascals, kilopascals, megapascals, bar, millibar, PSI, atmospheres and mmHg (Torr).

Energy - joules, kilojoules, megajoules, calories, kilocalories, watt-hours, kilowatt-hours and BTU.

Frequently asked questions

Length conversions

How many centimetres in an inch? 1 inch = 2.54 centimetres exactly. This is the defined relationship between the imperial and metric systems - it is not an approximation.

How many feet in a metre? 1 metre = 3.28084 feet. Alternatively, 1 foot = 0.3048 metres.

How many miles in a kilometre? 1 kilometre = 0.621371 miles. 1 mile = 1.609344 kilometres. A useful rough conversion: multiply kilometres by 0.6 to get approximate miles, or divide miles by 0.6 to get approximate kilometres.

How many inches in a foot? 12 inches = 1 foot. 1 foot = 12 inches. 1 yard = 3 feet = 36 inches.

How do I convert my height from feet and inches to centimetres? Convert the feet to inches first (multiply by 12), add the remaining inches, then multiply the total by 2.54. For example, 5 feet 8 inches = (5 × 12) + 8 = 68 inches × 2.54 = 172.72 cm.

Weight conversions

How many grams in an ounce? 1 ounce = 28.3495 grams. 1 gram = 0.035274 ounces.

How many kilograms in a pound? 1 pound = 0.453592 kilograms. 1 kilogram = 2.20462 pounds.

How many pounds in a stone? 1 stone = 14 pounds = 6.35029 kilograms.

How do I convert kilograms to stones and pounds? Divide the kilogram value by 6.35029 to get stones. The whole number is the stones; multiply the decimal by 14 to get the remaining pounds. For example, 80 kg ÷ 6.35029 = 12.598 stones = 12 stone 8.4 pounds.

What is the difference between mass and weight? In everyday use, mass and weight are used interchangeably. In physics, mass is the amount of matter in an object (measured in kilograms) and weight is the gravitational force on that mass (measured in newtons). On Earth, 1 kg of mass weighs approximately 9.81 newtons. For everyday conversions, treating mass and weight as equivalent is standard.

Temperature conversions

How do I convert Celsius to Fahrenheit? Multiply by 9, divide by 5, then add 32. The formula is: °F = (°C × 9/5) + 32. A quick mental approximation: double the Celsius temperature and add 30 (this is not exact but gives a useful rough figure).

How do I convert Fahrenheit to Celsius? Subtract 32, multiply by 5, then divide by 9. The formula is: °C = (°F − 32) × 5/9.

What is Kelvin and when is it used? Kelvin is the SI base unit for temperature, used in science and engineering. Zero Kelvin (0 K) is absolute zero - the coldest possible temperature, where all molecular motion stops. To convert Celsius to Kelvin: add 273.15. To convert Kelvin to Celsius: subtract 273.15. Kelvin does not use a degree symbol - it is written as K, not °K.

What temperature is the same in Celsius and Fahrenheit? −40 degrees is the same in both Celsius and Fahrenheit. −40°C = −40°F.

What is normal body temperature in Celsius and Fahrenheit? Normal body temperature is approximately 37°C or 98.6°F. In practice, normal temperature varies between individuals and ranges from about 36.1°C to 37.2°C (97°F to 99°F).

Volume conversions

How many millilitres in a pint? 1 UK pint = 568.261 millilitres. 1 US pint = 473.176 millilitres. The UK and US pint are different measurements - the UK pint is larger.

How many litres in a gallon? 1 UK gallon = 4.54609 litres. 1 US gallon = 3.78541 litres. If you are following a US recipe or fuel figure, use the US gallon.

How many teaspoons in a tablespoon? 3 teaspoons = 1 tablespoon (both UK and US, though the absolute volumes differ slightly). 1 UK tablespoon = 17.758 ml; 1 US tablespoon = 14.787 ml.

Why are UK and US measurements different for volume? The US customary system and the British imperial system diverged historically. The US gallon was defined differently from the UK gallon in the early 19th century. This means US and UK recipes using cups, pints and gallons will produce different quantities - always check which system a recipe uses.

How many cups in a litre? Using the US cup (236.588 ml): 1 litre = 4.227 US cups. There is no official UK cup measurement in the imperial system, though 250 ml is commonly used as a metric cup in UK recipes.

Area conversions

How many square feet in a square metre? 1 square metre = 10.7639 square feet. 1 square foot = 0.092903 square metres.

How many square metres in an acre? 1 acre = 4046.86 square metres. 1 hectare = 10,000 square metres = 2.47105 acres.

What is the difference between acres and hectares? Both measure land area. Acres are used in the UK and US imperial systems. Hectares are the metric equivalent used internationally and in scientific contexts. 1 hectare = 2.47105 acres; 1 acre = 0.404686 hectares. An acre is approximately the size of a football pitch.

Speed conversions

How many mph in a km/h? 1 km/h = 0.621371 mph. 1 mph = 1.60934 km/h. A rough conversion: multiply km/h by 0.6 to get approximate mph.

What is a knot? A knot is one nautical mile per hour - used for maritime and aviation speed. 1 knot = 1.85200 km/h = 1.15078 mph.

How fast is the speed of light? Approximately 299,792,458 metres per second - roughly 186,282 miles per second, or about 670,616,629 mph. The speed of light in a vacuum is a physical constant, denoted as c.

Data conversions

How many bytes in a kilobyte? In standard computing terms, 1 kilobyte = 1,024 bytes (using binary, base-2 measurement). 1 megabyte = 1,024 kilobytes = 1,048,576 bytes. This calculator uses the binary definition which is standard in computing contexts.

Why do hard drive manufacturers use different sizes than Windows shows? Hard drive manufacturers use the decimal definition (1 kilobyte = 1,000 bytes) while operating systems use the binary definition (1 kilobyte = 1,024 bytes). A 1 terabyte drive contains 1,000,000,000,000 bytes by the manufacturer's definition - Windows reports this as approximately 931 GB using the binary calculation.

Time conversions

How many seconds in a day? 60 seconds × 60 minutes × 24 hours = 86,400 seconds per day.

How many seconds in a year? Approximately 31,557,600 seconds, based on the Julian year of 365.25 days (accounting for leap years). A calendar year of exactly 365 days = 31,536,000 seconds.

Pressure conversions

What is PSI? PSI stands for pounds per square inch - the pressure unit used in the US and UK for tyre pressure, blood pressure and other everyday measurements. 1 PSI = 6894.76 pascals = 0.0689476 bar.

What should my tyre pressure be in bar vs PSI? A common car tyre pressure is 32 PSI = 2.21 bar. The recommended pressure for your vehicle is in the owner's manual or on a sticker inside the driver's door frame. This calculator converts between PSI and bar instantly.

What is atmospheric pressure in different units? Standard atmospheric pressure (1 atm) = 101,325 pascals = 1013.25 millibar = 14.6959 PSI = 760 mmHg.

Energy conversions

What is the difference between a calorie and a kilocalorie? In everyday food and nutrition, "calories" on food labels actually refers to kilocalories (kcal) - 1 food calorie = 1 kilocalorie = 4184 joules. In scientific contexts, 1 calorie = 4.184 joules. The food industry convention of writing kcal as "calories" causes widespread confusion.

How many kilowatt-hours in a megajoule? 1 kilowatt-hour = 3.6 megajoules. 1 megajoule = 0.277778 kilowatt-hours. Energy bills in the UK use kilowatt-hours (kWh) as the unit for electricity consumption.

What is a BTU? A British Thermal Unit (BTU) is the energy required to raise the temperature of one pound of water by one degree Fahrenheit. It is used for heating and air conditioning in the US and sometimes in the UK for boiler ratings. 1 BTU = 1055.06 joules = 0.000293071 kilowatt-hours.

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