An erg is the CGS (centimeter-gram-second) unit of energy, equal to one ten-millionth of a joule.
Ergs to Rontojoules
Convert Erg (erg) to Rontojoule (rJ) instantly with an exact formula, conversion table, and FAQ.
Reserved for a responsive leaderboard above the conversion details.
Professional calculator style
World-scale conversion engine
30+ categories
6,500+ units
Instant results
Offline ready
Energy calculator
Energy Converter
Convert ergs (erg) to rontojoules (rJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
rJ = erg × 1.000000000e+20
Results update instantly for Ergs to Rontojoules conversions.
Reserved above the conversion cards and below the converter.
Formula
rJ = erg × 1.000000000e+20
erg = rJ × 1.000000000e-20
Conversion table
| 1 erg | 1.000000e+20 rJ |
| 5 erg | 5.000000e+20 rJ |
| 10 erg | 1.000000e+21 rJ |
| 20 erg | 2.000000e+21 rJ |
| 50 erg | 5.000000e+21 rJ |
| 100 erg | 1.000000e+22 rJ |
| 500 erg | 5.000000e+22 rJ |
| 1000 erg | 1.000000e+23 rJ |
Related conversions
Reserved between the cards and the FAQ so the page stays balanced.
How the formula works
Both erg and rontojoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in ergs by 1.000000000e+20 to get rontojoules. To reverse the conversion, multiply a rontojoule value by 1.000000000e-20 to get back to ergs.
Frequently asked questions
What is Erg (erg)?
An erg is the CGS (centimeter-gram-second) unit of energy, equal to one ten-millionth of a joule.
What is Rontojoule (rJ)?
A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
How do I convert ergs to rontojoules?
Multiply the erg value by 1.000000000e+20 to get the equivalent in rontojoules. For example, 5 erg × 1.000000000e+20 = 5.000000e+20 rJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1.000000000e+20 is an exact, non-rounded value.
Can I convert rontojoules back to ergs?
Yes. Divide the rontojoule value by 1.000000000e+20, or multiply it by 1.000000000e-20, to get ergs.
Reserved between the FAQ and the article so the page stays balanced.
About converting ergs to rontojoules
An erg is the CGS (centimeter-gram-second) unit of energy, equal to one ten-millionth of a joule. A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
Use this calculator to move between ergs and rontojoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.