British Thermal Units to Quads (BTU to quad)
1 British thermal unit equals 1×10⁻¹⁵ quads exactly.
How to convert British thermal units to quads
To convert British thermal units to quads, multiply the number of British thermal units by 1×10⁻¹⁵. This factor is exact. To go the other way, multiply quads by 1×10¹⁵.
quads = British thermal units × 1×10⁻¹⁵
Example: 10 British thermal units = 1×10⁻¹⁴ quads.
The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.
About these units
British Thermal Unit (BTU)
The International Table BTU, exactly 1,055.05585262 joules. The energy to heat one pound of water by one degree Fahrenheit; used for heating, cooling and gas appliances in the US.
Few energy units come in as many versions as the British thermal unit. It was defined as the heat needed to raise one pound of liquid water by one degree Fahrenheit, but because water's heat capacity shifts slightly with temperature, definitions differ by up to 0.5 percent: about 1,054.35 J for the thermochemical Btu, 1,054.80 J at 59 degrees Fahrenheit (used for American natural gas pricing), 1,054.68 J at 60 degrees (mainly Canadian), and 1,059.67 J at 39 degrees. A 1942 note suggests the term apparently arose in the United States and was later adopted in Britain.
The version on this site is the International Table Btu, about 1,055.06 J, which comes from the international steam table conferences that tied heat units to the joule. Joule's own 1850 experiments gave 772.692 foot-pounds of work per Btu, the number that first linked heat to mechanical effort.
Today the Btu survives in natural gas pricing (MMBtu means a million Btu), US building energy reporting, and equipment ratings in Btu per hour. One ton of air-conditioning is 12,000 Btu/h, or 3.52 kW. A single wooden kitchen match burning releases about one Btu.
1 British thermal unit = 1,055.055853 joules (approximately).
Sources: Wikipedia: British thermal unit; Wikipedia: James Prescott Joule
Quad (quad)
One quadrillion BTU (about 1.055×10¹⁸ J). Used to quote national and global energy use; US consumption was about 100 quads in 2005.
Energy planners reach for the quad when joules or gallons become unwieldy. One quad is a quadrillion (10 to the 15th power) British thermal units, a figure the US Department of Energy uses for national and world energy budgets. In SI terms it is about 1.055 exajoules, or 1.055 times 10 to the 18th joules.
Which BTU applies changes the last digits. The figure used here, 1.05505585 times 10 to the 18th joules, corresponds to the International Table BTU of roughly 1,055.06 J. The 59 degree Fahrenheit BTU used in American gas pricing would give a value about 0.02 percent smaller, and the Wikipedia article on the quad does not say which BTU it assumes.
For scale, one quad equals about 8 billion US gallons of gasoline or roughly 293 terawatt-hours of electricity. Wikipedia reports world primary energy production of about 638 quads in 2022. In 2005 the US economy used close to 100 quads, so the unit suits country-sized totals rather than anything a household buys.
1 quad = 1.055055853×10¹⁸ joules (approximately).
Sources: Wikipedia: Quad (unit); EIA: British thermal units (Btu); Wikipedia: British thermal unit
Related conversions
- Quads to British thermal units (reverse)
- British thermal units to joules
- British thermal units to kilojoules
- British thermal units to watt-hours
- British thermal units to kilowatt-hours
- British thermal units to calories
- British thermal units to kilocalories
- British thermal units to megajoules
- British thermal units to gigajoules
- British thermal units to megawatt-hours
- British thermal units to foot-pounds
- British thermal units to millijoules
- British thermal units to electronvolts
- Joules to quads
- Kilojoules to quads
- Watt-hours to quads
- Kilowatt-hours to quads
- Calories to quads
- Kilocalories to quads
See all energy units.