Chart from this article
From best to worst, I've calculated each coach's winning % at their current school only. The number of seasons coached are in parentheses.
Chip Kelly - .846 (2)
Jim Tressel - .828 (10)
Bob Stoops - .806 (12)
Nick Saban - .796 (4)
Mack Brown - .796 (13)
Les Miles - .784 (6)
Bret Bielema - .753 (5)
Mark Richt - .738 (10)
Bo Pelini - .714 (3)
Jimbo Fisher - .714 (1)
Paul Johnson - .650 (3)
Jeff Tedford - .631 (9)
Lane Kiffin - .615 (1)
Gary Pinkel - .611 (10)
Bobby Petrino - .605 (3)
Kirk Ferentz - .597 (12)
Houston Nutt - .578 (3)
Steve Spurrier - .571 (6)
Jim Grobe - .508 (10)
Will Muschamp - N/A

From best to worst, I've calculated each coach's winning % at their current school only. The number of seasons coached are in parentheses.
Chip Kelly - .846 (2)
Jim Tressel - .828 (10)
Bob Stoops - .806 (12)
Nick Saban - .796 (4)
Mack Brown - .796 (13)
Les Miles - .784 (6)
Bret Bielema - .753 (5)
Mark Richt - .738 (10)
Bo Pelini - .714 (3)
Jimbo Fisher - .714 (1)
Paul Johnson - .650 (3)
Jeff Tedford - .631 (9)
Lane Kiffin - .615 (1)
Gary Pinkel - .611 (10)
Bobby Petrino - .605 (3)
Kirk Ferentz - .597 (12)
Houston Nutt - .578 (3)
Steve Spurrier - .571 (6)
Jim Grobe - .508 (10)
Will Muschamp - N/A