HomeFind a SchoolDefining Your Ideal School

How important is class size?

Class size is one of many factors to consider when choosing or evaluating a school.

By GreatSchools Staff

How much attention do students at your school get? Class size is one factor to consider when evaluating a school's effectiveness. But small class size alone does not ensure a good education. The quality of the teaching, the school leadership, the size of the school, the amount of parent involvement and other factors are important to consider, too.

What's the difference between class size and student-teacher ratio?

GreatSchools publishes class size information for schools in some states and student-teacher-ratio information in others, depending on what's available in each state from the respective state Department of Education. It's important to understand the difference between these two types of data and what they indicate about your school.

When you see class size stats on GreatSchools' school pages, the number refers to the average class size at the school. Some classes may be larger or smaller than the average number you see. This is especially true in schools which have state-mandated class sizes, particularly in the lower grades. Schools that have mandated lower class sizes in grades kindergarten through 3 may have larger class sizes for the upper grades.

Student-teacher ratios are based on the total number of school instructional staff divided by the total enrollment of students. So this number may include specialist teachers in the arts, literacy specialists, physical education and special education teachers, who may teach smaller groups of students. As a result, student-teacher ratios may show smaller numbers than the actual average class size.

Student-teacher ratios, which in many states are based upon full-time equivalent (FTE) teachers, can appear high for schools that have a large number of part-time teachers. If, for example, a small school has four part-time teachers, who each work 25% of the time, the student-teacher ratio at this school would be calculated based upon one teacher instead of four (because four teachers at 25% is equal to one full-time teacher). This will make the student-teacher ratio appear higher than it really is. If you think your school data shows an exceptionally high student-teacher ratio, check with your school principal to find out why.

What defines a "small class"?

Researchers have found that gains in achievement generally occur when class size is reduced to less than 20 students.

What are the benefits of small classes?

Numerous studies have been done to assess the impact of class size reduction. Although most studies do show a relationship between small class size and increased student achievement, researchers disagree on how to interpret the results. Because there are so many variables in the average classroom — the quality of the teacher, the home environment of the students, the quality of the curriculum, the leadership of the school — it is difficult to draw definitive conclusions about student achievement based on class size alone. In other words, strategies effective in one setting may not be equally effective in another. Nevertheless, studies over a period of years have pointed to a number of trends as a result of lowering class size:

  • Gains associated with small classes generally appear when the class size is reduced to less than 20 students.
  • Gains associated with small classes are stronger for the early grades.
  • Gains are stronger for students who come from groups that are traditionally disadvantaged in education — minorities and immigrants.
  • Gains from class size reduction in the early grades continue for students in the upper grades. Students are less likely to be retained, more likely to stay in school and more likely to earn better grades.
  • Academic gains are not the only benefit of lowering class size. A recent study published in the American Journal of Public Health revealed that reducing class sizes in elementary schools may be more cost-effective than most public health and medical interventions. This is because students in smaller classes are more likely to graduate from high school, and high school graduates earn more and also enjoy significantly better health than high school dropouts.

Next page: Why reducing class size matters in the early grades

Comments from readers

"There is way too many kids in the classroom the ratio is more like 32:1. Teacher is overwhelmed and is not aware of what going on in the class with the students "
"I'm of the old school. Children going to school must be pre-motivated. Perhaps all the PreK efforts should make sure that children are properly motivated before entering the 1st grade. Anyhow, 17 in a class is a joke. My elementary school had 60 in a class. ..and one nun. A class less than 20 is only an acknowledgment to failure of the system. It is obvious that China will far outpace our coddling education system . Very sad. "
"I don't think the people who are commenting are fully reading the articles. Yes, there are classes with more than 15 and 17 students, but, as it was stated in the articles, those numbers are averages. They are taken from every class, not just core curriculum classes. These numbers are derived from core curriculum classes, elective classes, P.E. classes, and special education classes. Also, these numbers reflect ELEMENTARY school classroom size averages, not secondary educations class sizes. "
"the board of education should re-read and understand this before placeing childern in the classroom "
"when there are three year olds mixed in with older children the ratio of student to teacher is 1 teacher for every 6 children. that means if you have one three year old and the rest are 4-6 you can only have a total of six children. Is this the case and if not how is this legal? "
"Smaller class sizes cost more money. There is no more money left because the federal government has mandated too many other things that school districts have to do instead. Instead of smaller class sizes, students receive extra testing instead. This extra testing isn't all, though. Since the federal government needs to have a scapegoat (teachers) to take the heat instead of the real problem (it's inability to reduce poverty), students also get weeks of mind-numbing review for these high-stakes tests. Since they need so much time for review, students also get a special curriculum--not everything they are supposed to learn, only what is most likely to appear on these tests. Many special things for the students instead of smaller class sizes. Thank you, government, for letting students Race to the Top. How about letting them learn instead? "
"when you take a good look at it the larger a class the less one on one you will have there are no good benefits to have larger classes at all the state needs to talk to teachers and then maybe they will get the big picture!!! "
"I was a student in the first class of a private school in Brooklyn, NY which began with almost no money. For the first two years, classes were held in a dank basement of an ancient building. The teachers were dedicated to excellence, the quality of the curriculum was superb and the thirty students performed in the highest percentile when tested. Of the thirty, three became neurosurgeons, another ten became physicians in various specialties, two are reknown Harvard Law School Professors, and two are self made billionaires. Throwing money at schools is not the answer. Demanding curricula, teachers who know their subjects and are committed to excellence, and stimulated and engaged students are the keys to success. "Garbage in, garbage out" is what you get when you water down expectations. We emerged from high school fluent in two languages and with a working knowledge of a third. We were made to read and discuss the classics. We were taught how to think. "
"People!! Learn to spell and use correct grammar,please. I don't think class size matters. It all depends on the student and the teacher.b "
"I have a five year old son attending Phillips for one year and he complains that the work is long and hard.This is a time in a child's life were school should not be looked at as a burden but as a learning tool to promote both academic and social skills. "
"its common sense that smaller class sizes are better less kids means more time for each individual student leading to better academics for our youth-_- yours trully the king of pop. "tee hee" "
"this helped me a lot on my project "
"this article helped me on my project :) "
"This really helps out a lot because I am doing a research on this "
"My daughter taught at Cienega and her class size was 33 in a core subject. Don't know where you are getting 17. "
"Sorry, but this is very misleading. This school's first and second grade classes are larger--22 in first, 25+ in second. "
"I am in Highschool my second year now. I was checking the laws. Florida's law of no more than 25 students makes sense. For an elective I think the classes should be smaller. I take art and we have two teachers the one I have has 34 students in the class. I asked to be swiched with the other teacher in what I was told was unlikely to be done. I fear I will not get the sufficent attention I need to pass or understand concepts. My question is if the class is 40 minutes and the teacher takes half of it explaining something doesn't that give me less then half a minute of actually having a 1 on 1 time with the instructor. I also wonder why they wouldn't change me. It is my choice after all and I wonder why they do not see how a student is reaching out for Thier own education. If you saw a student personally reaching out should you or would you not give them as they please. At least the student is being in school trying for an eduactaion while some skip class and just simply do not! care. Why don't the students that do care not have some type of justice done for them. As I explained there are many flaws in the laws and i hope they realize some schools do not listen and also some schools need funds to make more classes for the students to be on a more personal level with a teacher. Personally I was trying to make an effort for myself but then again why does the school care? By just saying no they showed they do not really care as much as the lead on. "
"I agree that smaller classroom sizes can help students do better because we classes are to large students do not get the help they need affects their grades "
"I'm looking for student profiles. Any links? "
"I'm in 8th and there is about 28 students in my room. The only teachers who have under 20 students are the special education teachers. And another thing the teachers don't personally get to know us here as they say they can. There's 9 periods and each teacher sees over 90 students a day. With 40 minute periods there's not much time for one on one talking with a teacher."
"It is a very mind changing artical."
"I think this school sound great I am thinging about seeing that my child gets to be a part of this school."
"yes i defiantly agree"
"i really like paradise school. it is the best school you can get in my opinion. it is 100 years old. please don't let is shut down though."
"Another benefit of smaller class size in the lower grades is the greater opportunity for a teacher to identify students that are struggling or falling behind. It also gives the teacher a better opportunity to intervene early, thus building a stronger foundation for future learning."
"It takes time for a teacher to individualize for each child, because every child is at a different stage of development."
"Yes, I true DO believe that the small classes are best for the teacher and students. The students will receive more quality time in the classroom. The teacher will spend more time quality teaching and less time disciplining. This is extremely important to get the students ready for high school and college. In the end, the school will get a higher rating. It will be a win win situation for everyone concerned."
"I am not surprised that the NEA recommends a no more than 15 students per class. They are a union who wants to employ more teachers. Where does the research come from that says small classes are needed to provide better education? It comes from teachers and their unions. Good teachers with a good curriculum and common sense are what is needed for all children to be educated. Good teachers can handle larger classes without any deterioration of curriculum."
"I will tell you this, reducing class size no matter what grade the children are in helps tremendously! My children went from an overcrowded school in Anne Arundel Co. Maryland to a same size school with smaller class sizes and it has made a world of difference...they love it and are thriving! I am afraid to move to Raleigh after seeing the class sizes and the over crowded schools and I know the one that my child will be attending and it is ridiculous the amount of children in just one school. As much money in taxes NC receives build more schools and fix the problem along with redistricting and put the children in the schools they belong in! "
"I am a baby boomer. I grew up when the schools were crowded. I remember there being 42 students in one class. In college I was taught the most important items in getting a good education are 1. teacher expectations 2. student expectations 3. parent expectation and 4 the student's peer group expectations. I cannot recommend the Centerville school system. If it wasn't for the very high quality of its students it would just be another mediocre school."
"I have always wondered how school districts were able to advertise student to teacher ratios instead of TRUE class size....Student to teacher ratios that school districts report in their statistical data are ALWAYS bogus. If a class has a full time teacher and a full time SPED teacher for one student in a class size of 26 kids....the district reports a Student to teacher ratio of 13. The SPED teacher does not teach the class, they only are responsible for that one child. It is very deceiving and quite dishonest. "
"GreatSchools' report on teacher-student ratio is incorrect for my kids' school. According to GreatSchool, the teacher-student ratio is 16 per classroom. But in fact, my daughter's classroom has 30-35 students and my son's classroom has 25-27 students for the past 2 years. The class size never went below 22 for this school."
"How do I share this article via email with the staff at my school?"
"I'm interested in finding out about exceptional teachers, teachers that are not a good fit for certain kids, specifics that help me advocate for my kid and his/her high school experience. Is there a place on this web site? Or is there another web site?"
"I am concerned about the way 'Great Schools' is reporting class size. They are simply looking at the number of teachers vs the number of students. Many teachers in the count teach speech or special education. A school may seem to have an average class size of 23 but actually a few classes many be lower or higher. Our district has 30-35 in every class except special ed classes. There is no way I am able to meet the needs of all these children! "
"It amazes me at how one can skew research to meet the need of the study. Common sense tells one that needy students need more teacher contact and that they will only succeed when relationships and quality instruction are a part of everyday. Class sizes of over 20 are not the only answer to student learning, but play an integral part in poverty schools. Please realize the extraneous circumstances that surround schools do not allow equal to be the same as equitable. Disadvantaged students need more attention, better quality instructors, and smaller class sizes to be successful."
"Well to be honest with you.When it is a little class amount we do get a better education,because not many kids are there to pick on you about what you dont know.It helps because you are one on one with the teachers and they can help you to the best of your ability to what you know.And you are able to put your best foot forward into all your work and answer and alot of the kids get along so no fights and drama. status:wmms student"
"Reduced class size is important to me. I just enrolled my son into a charter school with class sizes of 20 children. I am concerned that my son will not receive the same education, attention and advantages that he received in private school with a class size of 12. How can I be put at ease an feel more comfident about my chose? "
"The teacher/student ratio is inaccurate. My child at Brown Barge has about 30 students per class. So where does the 15 number come from? Class size is important. We can not be compared with asian countries. There are major differences. They can still reprimand students with the knowledge that officials are behind them. A large class with a few unruly students can change the learning environment. Don't blame this on the teachers but blame it on the district that has not established a viable alternative."
"In response to the person wanting to know how thier child would be clasified. no different than any other child in that school. no matter if the child has a learning disability or not. They are all treated equal and if some one does need more help than another then another older student works with them or a teacher's helper (a parent) but no child is ignored because the class size is small."
"if i send my child to that school will he be clasifyed because lets be honest that school has children with special needs n i wan kno will they be clasifyed for attending this school"
"size of class is important 25 children to one teacher to much I've seen it no control at all "
"You might want to double check what you are reporting as 'class size'...This school year every classroom at Polk elementary in Dearborn heights MI has 30 children, not 24."
"Class size is not as important as people make it out to be. In many countries in Asia, there are thirty to forty kids in a class with one teacher. Yet, they seem to learn very well - as much as they are expected to or better. Even with 12 kids, it's not possible for a teacher to sit down and have every kid understand every concept that is taught. Also, learning is two-faced. There are the 'understanding' part and the 'repeat-until-you-master' part. What we need is more discipline and parental involvement at home (not even at school). We shouldn't make a such a big deal about volunteering at school, either. Teachers should impart knowledge through lessons. Parents should monitor and help with kids' progress. Besides, teachers are not educated enough to be completely responsible for your children's learning. That is if you are going for excellence."
"i love this school it is great "
"Class size, school size, district size, attitude, and atmosphere affect learning. In the district where we live there are 3 elementary schools: one with over 2,000 students, a new school with around 1,000, and a small country school with 3 teachers, one of whom is also the principal. Grades K-3 have a 20- student limit. Upper grades allow almost twice as many! A close friend moved from 5th to 3rd so she could really get to know and reach out to each of her students as well as perform the ever-growing, time-consuming, non-teaching, under-appreciated extra tasks required of teachers. My granddaughter's teacher this year was neither very caring nor helpful. None of the 9 other first-grade classes at the school had any room, and the administration couldn't force someone switch. The only school with room for another first grader was the little one miles away. There are 2 other districts with schools closer than that! We opted for Faith Academy, a small K-8 Christian school. It is close, has a caring staff, offers an after-school program till 5:30 for $5.00 a day, and costs about $200 less per month than preschool did. Of course everyone participates in fundraisers. I believe that small classes are needed for K-6, and also all the way through college for subjects such as learning another language, where participation and interaction are crucial, and/or that require a lot of teacher time outside of class to read, evaluate, and provide constructive feed-back such as in a writing class. Small schools are better where students are in self-contained classrooms. In junior high and especially in high school and college, students of larger schools often have a bigger choice of courses, especially if small classes do not fall victim to school or district 'politics.' "
"I suspect the writer of this article was a conservative Republican. I was amazed that I did not read that you would prefer to take take school funding away from public schools and hand those tax dollars over to some type of parochial religous school that would not teach anything about sex education except total abstinence; that you would prefer you children learn about Adam and Eve in the Garden of Eden instead of learning about evolution; and that teaching anything about global warming should be totally out lawed in any school that your children would attend. Without a doubt, public school education has been the foundation of every single great leader this county has ever produced. And millions of children have been educated by public school teachers who have stood up and screamed and hollered and had to get down on their knees and beg the public to produce the dollars for the programs that have been so successful in educating all colors of children throughout this country while racist politicians and media have attempted to establish a 'haves' and the 'have nots' society by taking away tax dollars from the public schools full of dedicated teachers who have struggled to teach poor students from the worst of neighborhoods in this country and students of immigrants who do not speak the English language in the home. Teachers cannot plug a student into a wall socket and expect children from all walks of life, with varying degrees of experiences to take in, assimilate, and reguritate all the correct answers on a state test. No Child Gets Left Behind in public schools in this country even though Geo Dubyah Bush attempted to dismantle public schools by cutting off the funding needed. "
"When the mandate to reduce class size in the elementary schools hit the Placentia/Yorba schools, it was a scramble to attract and hire qualified teachers. Because of the area, finding great teachers was for the most part no problem. The point is top teachers like to live and work in nice communities. Having a large supportive parent base for volunteer programs and field trips didn't hurt either. My kids now go to an overly large high school - Esperanza. Class size is larger than average, however, doesn't seem to impact the teachers ability to teach or the kids ability to absorb the learning. Point is, I now believe that a a strong elementary school education in the basics is extremely important to the later learning skills and that the teacher/parent team is everything to the success of a child in school. "
"Class size is important..Although next year Los Angeles Unified School district is increasing their class size due to major budget cuts. In LAUSD there will also be a major teacher layoff, many principals and coaches will be forced back into the classroom, which will bump out any newly hired teachers, due to senority.The district may not have enough $$ to function in the year 2010-2011."
"I agree that class size DOES matter, but i enrolled my daughter in summit academy middle school and her class sizes are fairly large still (equivelant to regular public school) yet, the teaching staff seems to be MUCH stronger-therefore she's doing better. Grades and behavior- and thats all that matters! She would like to still try our public middle school, but i think she's just fine where she's at."
"Class size matters. with 30-35 student in the class rom the student achievement is poor. I don't like that, the boar of educacion have to do something, this is why some student are d d f f, because teacher have not time for them. is too much 30 student for one teacher."
"I believe that smaller classes for all are best but as they get older it's not SOOO needed. The kindergartens are new to the system. Have been home with parents or is small preschool classes and have to learn to trust what is going on. As they get older they are more confident. I think High schoolers are better is smaller schools but not so much from smaller classes. They know what is going on, don't need to be one on one with the teachers so much and are preparing to college or the real world. My daughters school is great, we moved her because it was. She is in a class of only 18 kids and she's in kindergarten and loves it. It's only up to 4th grade and there are 3 kindergarten teachers. I can't say i remember the full student count. But i think we need to Make them lower the student count if the count is over 20. But know one listens. Good luck with that."
"Class size is UNIMPORTANT. Discipline is important. Remember that when these kids are in UC's and CalState, they will be in a class with 300 other students if not more for Math 101 - with one teacher and 10 TA's. Small class size is a function of the strength of teachers' unions who couldn't care a *&$^ about the quality of education [of course they will say and preach otherwise]. Bottom-line: Class size does not and will not affect learning. If it does, then none of our kids should go to college. Rob"
"I'm a substitute in New Mexico. Where a 1st grade class has as many as 28 students. The students can go to any school of there choosing. Not staying in there own districts.Which of course makes for overcrowded classrooms and exhausted teachers. Besides the child that goes to a school where he shouldn't be. Takes the place of the child who should be.I believe if your a new teacher maybe you can get a smaller class the first year. Work your way up from there.For a first time teacher and 28 children,that's a bit intimidating don't you think.LCPS is in a sad shape and in a bad state of mind.So bad that even the subs are not showing up for assignments.Except for myself,I just don't get the calls I use to.B/c I hear the teachers were reprimanded on taking to many days off. Gee,I wonder why ? But here, if you don't use them you loose them ? Now how is that suppose to work ? I'm glad I'm not a teacher for the district. As a sub I can pick and choose.Oh,as Subs here we make $69.00 a day. I haven't seen a raise in the 5years I've for them !"