| Career - ERA | |||
| Rk | Player Name | Totals | |
| 1 | Jacob deGrom | 3.26 | |
| 2 | Mike Remlinger | 3.62 | |
| 3 | Randy Johnson | 3.70 | |
| 4 | Steve Reed | 3.71 | |
| 5 | Curt Schilling | 3.77 | |
| 6 | Max Scherzer | 3.79 | |
| 7 | Mike Moore | 4.00 | |
| 8 | Carlos Rodon | 4.12 | |
| 9 | Chuck Finley | 4.24 | |
| 10 | Andy Pettitte | 4.25 | |
| 11 | Chris Carpenter | 4.44 | |
| 12 | Mark Langston | 4.44 | |
| 13 | Pedro Astacio | 4.45 | |
| 14 | Madison Bumgarner | 4.55 | |
| 15 | Shaun Marcum | 4.55 | |
| 16 | Jason Schmidt | 4.56 | |
| 17 | Charlie Hough | 4.77 | |
| 18 | Kyle Gibson | 4.91 | |
| 19 | Robbie Ray | 5.02 | |
| 20 | Zack Greinke | 5.03 | |
| 21 | Pat Rapp | 5.08 | |
| 22 | Armando Reynoso | 5.21 | |
| 23 | Brian Holman | 5.25 | |
| 24 | Alex Wood | 5.36 | |
| 25 | Kevin Appier | 5.42 | |
| Single Season - ERA | |||||
| Rk | Player Name | Totals | Year | ||
| 1 | Charlie Hough | 2.37 | 1993 | ||
| 2 | Max Scherzer | 2.48 | 2019 | ||
| 3 | Jacob deGrom | 2.55 | 2019 | ||
| 4 | Max Scherzer | 2.67 | 2023 | ||
| 5 | Randy Johnson | 2.68 | 2005 | ||
| 6 | Mark Langston | 2.74 | 1993 | ||
| 7 | Curt Schilling | 2.83 | 2003 | ||
| 8 | Carlos Rodon | 2.92 | 2023 | ||
| 9 | Jacob deGrom | 2.93 | 2015 | ||
| 10 | Max Scherzer | 2.94 | 2018 | ||
| 11 | Jose Quintana | 2.94 | 2023 | ||
| 12 | Jacob deGrom | 2.97 | 2016 | ||
| 13 | Mike Moore | 3.01 | 1992 | ||
| 14 | Carlos Rodon | 3.07 | 2022 | ||
| 15 | Madison Bumgarner | 3.10 | 2015 | ||
| 16 | Chuck Finley | 3.14 | 1996 | ||
| 17 | Randy Johnson | 3.17 | 2002 | ||
| 18 | Chuck Finley | 3.33 | 1993 | ||
| 19 | Max Scherzer | 3.37 | 2022 | ||
| 20 | Madison Bumgarner | 3.41 | 2014 | ||
| 21 | Ross Detwiler | 3.42 | 2012 | ||
| 22 | Jacob deGrom | 3.43 | 2017 | ||
| 23 | Mike Moore | 3.48 | 1993 | ||
| 24 | Madison Bumgarner | 3.49 | 2018 | ||
| 25 | Shaun Marcum | 3.54 | 2011 | ||