Physics Converters

Convert joules, kilojoules and watts, and light years and parsecs.

These converters cover two separate areas of physics. The first is energy and power. A joule is a unit of energy and a watt is a rate, one joule per second, so joules and watts can only be converted when you also know the time. The joules to watts and watts to joules converters therefore ask for a duration as well as a value, while joules to kilojoules and kilojoules to joules simply divide or multiply by exactly 1,000.

The second is astronomical distance. A light year is the distance light travels in a year, the parsec is a unit astronomers use for the distances between stars, and one parsec is about 3.26 light years. Use light years to parsecs or parsecs to light years to move between popular-science figures and astronomy references. Rounded results are fine for comparison, but keep the unrounded factor if the number feeds into further work.

Popular physics converters

• Joules to Watts ConverterAverage power from an amount of energy and the time it takes.
• Watts to Joules ConverterEnergy transferred from a power rating and how long it runs.
• Light years to Parsecs ConverterLight years to parsecs, rounded to six decimals.
• Joules to KiloJoules ConverterJoules to kilojoules by dividing by exactly 1,000.

All physics converters

• Joules to KiloJoules ConverterEnter an energy in joules and the converter shows it in kilojoules at once. A kilojoule is a thousand joules, so the answer is your value divided by 1,000.
• Joules to Watts ConverterEnter an amount of energy and the time it is delivered or used over, and the converter returns the average power in milliwatts, watts, kilowatts or megawatts. A joule has no wattage of its own: power always needs a duration.
• KiloJoules to Joules ConverterType an energy in joules and its value in kilojoules appears below, or type in the kilojoule box to get joules. The two units differ by a fixed factor of exactly 1,000.
• Light years to Parsecs ConverterEnter a distance in light years and the converter returns parsecs, rounded to six decimals. One light year is about 0.3066 parsec, so a parsec is roughly three and a quarter light years.
• Parsecs to Light years ConverterEnter a distance in parsecs and the converter gives light years, rounded to four decimals. One parsec is a little over three and a quarter light years.
• Watts to Joules ConverterEnter a power rating and how long it runs, and the converter returns the energy transferred in joules, kilojoules or megajoules. Watts alone cannot give joules, so a time is always part of the calculation.