The average graduation rate of Top Colleges in Iowa is 62.70%. Grinnell College has the highest graduation rate of 88% and William Penn University has the lowest graduation rate of 33%The average transfer-out rate is 22.20% and the average retention rate is 77.60% Table. Top Colleges in Iowa Graduation Rate Comparison RankSchoolGraduation RateTransfer-out RateRetention RateStudents to Faculty Ratio 1Grinnell CollegeGrinnell, IA88%-93%9 to 1 2Drake UniversityDes Moines, IA74%-84%11 to 1 3Simpson CollegeIndianola, IA63%-81%12 to 1 4Luther CollegeDecorah, IA71%13%77%9 to 1 5Iowa State UniversityAmes, IA75%19%88%18 to 1 6Wartburg CollegeWaverly, IA64%26%76%13 to 1 7William Penn UniversityOskaloosa, IA33%-58%15 to 1 8Maharishi International UniversityFairfield, IA50%-61%13 to 1 9University of IowaIowa City, IA75%17%90%16 to 1 10Upper Iowa UniversityFayette, IA34%36%68%25 to 1-Average62.7000%22.2000%77.6000%14.1000 to 1