Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 erg | 9.478e-14 BTU | |
| 0.01 erg | 9.478e-13 BTU | |
| 0.1 erg | 9.478e-12 BTU | |
| 1 erg | 9.478e-11 BTU | |
| 5 erg | 4.739e-10 BTU | |
| 10 erg | 9.478e-10 BTU | |
| 50 erg | 4.73907e-09 BTU | |
| 100 erg | 9.47813e-09 BTU | |
| 1000 erg | 9.47813e-08 BTU |
Formula: BTU = Erg × 9.4781e-11
Multiply any erg value by 9.4781e-11 to get btu.
Reverse: Erg = BTU × 1.055e+10
Common erg values — factor: 1 erg = 9.4781e-11 BTU
| Erg (erg) | BTU (BTU) | Context |
|---|---|---|
| 1 erg | 9.478e-11 BTU | 1 erg |
| 100 erg | 9.478e-09 BTU | 100 erg |
| 1e+04 erg | 9.478e-07 BTU | 1 mJ |
| 1e+06 erg | 9.478e-05 BTU | 100 mJ |
| 1e+07 erg | 0.0009478 BTU | 1 J |
| 1e+08 erg | 0.009478 BTU | 10 J |
| 1.000e+10 erg | 0.9478 BTU | 1 kJ |
| 1.000e+12 erg | 94.78 BTU | 100 kJ |
| 1.000e+14 erg | 9,478 BTU | 10 MJ |
| 1.000e+17 erg | 9.478e+06 BTU | 1 GJ |
| 1.000e+20 erg | 9.478e+09 BTU | 100 GJ |
| 1.000e+23 erg | 9.478e+12 BTU | 10 TJ |
| 1.000e+26 erg | 9.478e+15 BTU | 1 PJ |
| 1.000e+30 erg | 9.478e+19 BTU | 1 EJ |
| 1.000e+33 erg | 9.478e+22 BTU | 1 ZJ |
1 erg = 9.4781e-11 BTU. Memorize for instant estimates.
Use 9.4781e-11 as a quick mental multiplier.
Multiply result by 1.055e+10 to recover the original erg value.
Sizes heating and cooling systems rated in BTU/hour for US buildings.
Certifies boiler output and efficiency ratings in BTU/hour.
Prices natural gas supply and usage in BTU and therms.
Calculates heating loads and heat loss in BTU for US properties.
Rates commercial refrigeration and ice-making capacity in BTU.
Specifies heat exchanger capacity and furnace output in BTU/hour.
The erg is the unit of energy in the CGS (centimeter-gram-second) system, equal to exactly 10⁻⁷ joules. It was defined by the British Association for the Advancement of Science in 1882 as the work done by a force of one dyne over one centimeter.
Ergs were widely used in 19th and early 20th century physics before SI standardization. They remain in use in astrophysics (stellar luminosities in erg/s) and some older scientific literature.
Interesting fact: The Sun radiates about 3.8 × 10³³ ergs per second. A mosquito in flight exerts about 100 ergs of energy per wingbeat. One joule = 10,000,000 ergs exactly.
The British Thermal Unit (BTU) is the traditional Imperial energy unit, defined as the heat required to raise 1 pound of water by 1°F. It equals 1,055.06 joules and has been used since the 19th century in heating, air conditioning, and gas billing.
BTU remains dominant in US HVAC: air conditioners and heaters are rated in BTU/hour. Natural gas is priced in therms (100,000 BTU) in the US. Furnaces are rated in BTU/hour output.
Interesting fact: A typical US home furnace is rated at 80,000–120,000 BTU/hour. One BTU is roughly the energy released by burning one kitchen match. The US natural gas pipeline system delivers about 25 quadrillion BTU (quads) per year.
Converting erg to btu is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 erg = 4.7391e-10 BTU and 10 erg = 9.4781e-10 BTU. Reverse: 1 BTU = 1.055e+10 erg. Exact factor: 1 erg = 9.4781e-11 BTU.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.