Ergs (erg) to British Thermal Units (IT) (BTU) conversion

1 erg = 9.478171e-11 BTUBTU → erg
Formula
1 erg = 9.478171e-11 BTU

Understanding Ergs to British Thermal Units (IT) Conversion

The erg is the energy unit of the CGS system, equal to 10−710⁻⁷ joules, still encountered in astrophysics, plasma physics, and older mechanics literature. The British Thermal Unit (IT) is an Imperial energy unit, the International Table BTU of about 1055.06 joules, widely used in HVAC, heating, and the US energy industry. Converting ergs to BTU bridges small CGS mechanical energies and the large thermal quantities of building and process engineering.

Conversion Formula

1 erg=9.478171×10−11 BTU1\ \text{erg} = 9.478171 \times 10⁻¹¹\ \text{BTU}

To convert Ergs to British Thermal Units (IT), multiply by this factor:

BTU=erg×9.478171×10−11\text{BTU} = \text{erg} \times 9.478171 \times 10⁻¹¹

Step-by-Step Example

Convert 25 Ergs to British Thermal Units (IT).

BTU=25×9.478171×10−11=2.369543×10−9 BTU\text{BTU} = 25 \times 9.478171 \times 10⁻¹¹ = 2.369543 \times 10⁻⁹\ \text{BTU}

How to Convert Ergs to British Thermal Units (IT)

Move a CGS energy into the thermal BTU used in heating engineering.

  1. Note the value in ergs: Start with the energy in ergs, e.g. 25 ergs.
  2. Multiply by the factor: Apply 9.478171×10−119.478171 \times 10⁻¹¹ BTU per erg.
  3. Calculate: 25×9.478171×10−1125 \times 9.478171 \times 10⁻¹¹.
  4. Report the answer: 25 ergs equal 2.369543×10−92.369543 \times 10⁻⁹ BTU.

Ergs to British Thermal Units (IT) conversion table

Ergs (erg)British Thermal Units (IT) (BTU)
00
19.478171e-11
21.895634e-10
32.843451e-10
43.791268e-10
54.739086e-10
65.686903e-10
76.63472e-10
87.582537e-10
98.530354e-10
109.478171e-10
151.421726e-9
201.895634e-9
252.369543e-9
302.843451e-9
403.791268e-9
504.739086e-9
605.686903e-9
706.63472e-9
807.582537e-9
908.530354e-9
1009.478171e-9
1501.421726e-8
2001.895634e-8
2502.369543e-8
3002.843451e-8
4003.791268e-8
5004.739086e-8
6005.686903e-8
7006.63472e-8
8007.582537e-8
9008.530354e-8
10009.478171e-8
20001.895634e-7
30002.843451e-7
40003.791268e-7
50004.739086e-7
100009.478171e-7
250000.000002369543
500000.000004739086
1000000.000009478171
2500000.00002369543
5000000.00004739086
10000000.00009478171

What is the Erg?

The erg is a unit of energy in the centimetre-gram-second (CGS) system, historically common in physics, astronomy, and mechanics before the SI joule became standard.

Definition

One erg is the work done by a force of one dyne acting over a distance of one centimetre:

1 erg=1.00000×10−7 J1\ \text{erg} = 1.00000 \times 10⁻⁷\ \text{J}

This equals exactly one ten-millionth of a joule (10⁻⁷ J), or equivalently 1 g·cm²/s². The erg is a small unit, reflecting the small base units of the CGS system.

Origin and History

The name comes from the Greek ergon, meaning "work." The unit was formally adopted by the British Association for the Advancement of Science in 1873 as part of the CGS system and remained the dominant energy unit in physics literature well into the 20th century.

Law and Notable Facts

The erg has been largely superseded by the joule and is deprecated in the modern SI framework, but it persists in astrophysics, where luminosities and energies are still frequently quoted in ergs and erg per second.

Real-World Examples and Conversions

  • 1 joule equals 10 million ergs.
  • A mosquito in flight expends energy on the order of a few ergs per wingbeat.
  • The Sun radiates about 3.8 × 10³³ ergs every second, equivalent to 3.8 × 10²⁶ watts.

What is the British Thermal Unit (IT)?

The British thermal unit (IT) is a unit of energy in the imperial and US customary systems, defined as roughly the heat needed to raise the temperature of one pound of water by one degree Fahrenheit. It is widely used in heating, cooling, and the power industries.

Definition

The "IT" (International Steam Table) British thermal unit is defined exactly in terms of the SI joule.

1 BTU=1055.06 J1\ \text{BTU} = 1055.06\ \text{J}

The exact value is 1 BTU (IT) = 1055.05585262 J. This IT definition is fixed by convention (derived from 1 BTU_IT = 1055.05585262 J, i.e. based on the International Steam Table calorie of 4.1868 J). It differs slightly from the thermochemical BTU (1054.35 J) and the mean BTU, because the amount of heat to warm water depends on the starting temperature.

Origin and History

The BTU arose in the 19th century alongside the calorie as engineers sought a practical unit tied to water and everyday temperature scales. Multiple definitions emerged (39 °F, 60 °F, mean, thermochemical), and the International Steam Table conference of 1956 fixed the IT calorie, and hence the IT BTU, to a precise joule value.

Law and Notable Facts

In the United States, air conditioners and furnaces are rated in BTU per hour, and natural gas is sold in therms (1 therm = 100,000 BTU). One "ton" of cooling equals 12,000 BTU/h, historically the heat absorbed by melting one short ton of ice in 24 hours.

Real-World Examples and Conversions

  • 1 BTU ≈ 1055 J ≈ 0.293071 watt-hour; a 5000 BTU/h window air conditioner draws about 1465 W of cooling.
  • 1 BTU is roughly the energy released by burning one wooden match.
  • 1 kWh = 3412.14 BTU, and 1 therm = 105.506 MJ.

Frequently Asked Questions

How many BTU are in one erg?

One erg equals 9.478171×10−119.478171 \times 10⁻¹¹ BTU (IT), reflecting how tiny a CGS energy unit is next to a thermal BTU.

How do I convert ergs to British Thermal Units?

Multiply the erg value by 9.478171×10−119.478171 \times 10⁻¹¹. For example, 25 ergs equal 2.369543×10−92.369543 \times 10⁻⁹ BTU.

How many ergs make up one BTU?

About 1.055056×10101.055056 \times 10¹⁰ ergs are needed to equal a single BTU (IT).

Why convert between these units?

Astrophysics and older mechanics work in ergs, while HVAC and heating engineering use BTU, so this conversion links the two conventions when comparing energy figures.

Which BTU definition does this use?

It uses the International Table BTU (IT) of about 1055.06 joules, the standard in most engineering references.

People also convert

erg to Wserg to Wmerg to Wherg to mWherg to kWherg to MWherg to GWherg to J

Complete Ergs conversion table

erg
UnitResult
Watt-seconds (Ws)1e-7 Ws
Watt-minutes (Wm)1.666667e-9 Wm
Watt-hours (Wh)2.777778e-11 Wh
Milliwatt-hours (mWh)2.777778e-8 mWh
Kilowatt-hours (kWh)2.777778e-14 kWh
Megawatt-hours (MWh)2.777778e-17 MWh
Gigawatt-hours (GWh)2.777778e-20 GWh
Joules (J)1e-7 J
Kilojoules (kJ)1e-10 kJ
Megajoules (MJ)1e-13 MJ
Gigajoules (GJ)1e-16 GJ
British Thermal Units (IT) (BTU)9.478171e-11 BTU
US Therms (thm)9.480434e-16 thm
Electronvolts (eV)624150900000 eV
Foot-pounds (ft-lbf)7.375621e-8 ft-lbf
Tonnes of TNT (t-tnt)2.390057e-17 t-tnt
calories (cal)2.390057e-8 cal
Kilocalories (kcal)2.390057e-11 kcal

Energy conversions