Estimated Class Sizes: More Than 90 National Universities

Editor’s note: Updated in September 15, 2019, to reflect most recent data.

Parents and prospective students are often interested in the average size of course sections. Assessing class size is extremely difficult because, first, a “class” has to be defined. Why is that difficult?

Some main sections (often in intro science, economics, business, etc.) may be very large, well in excess of 100 students, but the breakout labs and discussion sections are much smaller. Should  only the main section be counted, or should the labs and discussion sections also be included?

The best source for class size information and interesting data in general is the Common Data Set. Some universities publish their submissions, while others do not. The data in the CDS are used by U.S. News for many purposes, including the calculation of the percentage of classes with fewer than 20 students and the percentage of classes with more than 50 students. Using that information, we can also calculate the percentage of classes with enrollments between 20 and 50 students.

U.S. News does not include tutorials, thesis research, lab or discussion sections, and neither do we in our estimates of class sizes for honors programs. According to our counts, the average public university honors-only class section has 17.54 students. When we include honors credit classes that also have non-honors students, the overall average class size is 24.9 students. Both of these numbers are better than in 2016. This is an important consideration, given that the tables below show that public universities as a whole have significantly larger class sizes, and several have increased over 2016.

The next level of difficulty when using U.S. News data is to plug in an average number for the three class size groupings. For the group of fewer than 20 students, we are using an average of 17.5 students per section; for the group of classes with 20-50 students, we are using an average of 35 students; and for the group of classes with more than 50 students, we are using an average of 110 students.

The table below shows the percentage of classes in each size category along with the increase or decrease in the overall class size average since 2016. Universities are in rank order according to lowest estimated overall class size in 2020.

Class Sizes 2020       
University% <20% >50% 20 to 50% <5020202016Difference
Northwestern78.3516.79525.047526.95-1.9025
Chicago78.9615.19425.692526.025-0.3325
Columbia82.198.99127.382527.4-0.0174
Northeastern67.2626.89427.7429.8-2.06
Duke71.4721.69327.75526.7251.03
Tufts69.4723.69328.10528.175-0.07
Rice71.9820.19228.417529.1-0.6825
Penn718219228.57530.775-2.2
Tulane626329428.6528.1250.525
Vanderbilt65.9727.19328.717530.2-1.4825
Rochester74.1916.99128.782531.925-3.1425
Johns Hopkins73.6917.49128.8729.9-1.03
Yale73.4517.69128.90528.6250.28
Georgetown60.5633.59428.912529.575-0.6625
Dartmouth62.1730.99329.382529.8-0.4175
Princeton7410169029.5530.65-1.1
Caltech67.7923.39129.902530.025-0.1225
Harvard71.71018.39029.952529.550.4025
Brown69.91020.19030.267530.6-0.3325
Boston College48.6645.49430.99531.15-0.155
NYU61.1929.99131.057530.3250.7325
Stanford68.81120.28931.21310.21
MIT70.81217.28831.6133.775-2.165
Notre Dame61.91028.19031.667532.35-0.6825
Syracuse56.8934.29131.8130.7251.085
Carnegie Mellon66.41221.68832.3831.8750.505
Wash U63.91224.18832.817531.71.1175
U of Miami50.1940.99132.982531.91.0825
Boston Univ6212268833.1533.5-0.35
Brandeis57.21131.88933.2431.651.59
RPI52.41037.69033.3334.9-1.57
Geo Washington52.81136.28934.0132.5251.485
Florida St56.61231.48834.09541.225-7.13
Temple38.6853.49234.24534.35-0.105
Emory6013278734.2531.0753.175
Case Western59.11327.98734.407533.90.5075
USC58.81328.28734.4634.775-0.315
Oklahoma45.31143.78935.322535.9-0.5775
Georgia45.21143.88935.3434.9250.41
BYU45.21242.88836.0932.5253.565
Kansas48.91338.18736.192535.3750.8175
Virginia55.11529.98536.607536.625-0.0174
Iowa50.81435.28636.6135.8250.785
Florida50.11435.98636.732538.425-1.6925
North Carolina38.41249.68837.2839.425-2.145
Georgia Tech45.31440.78637.572546.925-9.3525
Cornell56.81726.28337.8138.875-1.065
Connecticut52.41631.68437.8337.150.68
Michigan56.81825.28238.5638.875-0.315
Arizona44.61639.48439.19539.425-0.23
UCSB50.21831.88239.71539.925-0.2099
Kentucky36.91548.18539.792541.75-1.9575
Massachusetts49.21832.88239.8941.375-1.485
Maryland44.81738.28339.9139.1250.785
UC Berkeley5319288139.97535.9254.05
Colorado44.11738.98340.032537.852.1825
LSU40.81742.28340.6144.275-3.665
Pitt44.51837.58240.712543-2.2875
NC State34.61649.48440.94542.85-1.905
Missouri38.71744.38340.977540.750.2275
Tennessee301555854140.60.4
Delaware33.91650.18441.067540.650.4175
Indiana37.31745.78341.222542.2-0.9775
South Carolina3717468341.27540.1751.1
Auburn35.11747.98341.607541.40.2075
Arizona State37.91844.18241.867541.3250.5425
Nebraska35.41846.68242.30540.9251.38
Penn State3117528342.32539.62.725
UCLA50.62227.47842.64542.5750.07
Utah37.31943.78142.722537.55.2225
UC Irvine53.22323.87742.9439.853.09
Oregon38.92041.18043.192542.8250.3675
Purdue38.32041.78043.297541.6751.6225
Illinois38.12041.98043.332542.650.6825
Minnesota37.52042.58043.437543.350.0875
Rutgers New Bruns41.62137.47943.4743.350.12
Wisconsin44.82233.27843.6641.951.71
Illinois Chicago34.52045.58043.962542.4251.5375
Oregon St31.42048.68044.50545.675-1.17
Iowa St2920518044.92547.575-2.65
Washington St32.62146.47945.04544.450.595
Virginia Tech27.42250.67846.70545.11.605
U at Buffalo SUNY29.32347.77747.122543.73.4225
Stony Brook SUNY3625397547.4542.1255.325
UT Austin37.62636.47447.9247.2750.645
Michigan State23.82353.27748.08548.8-0.715
Colorado St26.62449.47648.34541.856.495
Washington29.22545.87548.6445.3753.265
UC Davis36.22934.87150.41549.1251.29
Ohio State26.62746.47350.59546.254.345
Texas A&M21.42751.67351.50550.650.855
UCSD42.73225.36851.527555.35-3.8225
Mean Averages49.835814.978235.142384.978237.545037.41350.1314