| Index | St. Clair | Missouri | National |
| Average Test Scores | 42% | 44% | 48% |
| Student/Teacher ratio | 17:1 | 14:1 | 16:1 |
| Total public schools | 5 | 1,899 | 79,221 |
| Total private schools | 1 | 531 | 24,874 |
| Total post-secondary schools | n/a | 213 | 7,963 |

| Index | St. Clair | Missouri | National |
| Completed 8th grade | 77.0% | 86.0% | 84.3% |
| Completed high school | 73.5% | 84.2% | 83.0% |
| Completed some college | 43.1% | 57.7% | 59.4% |
| Completed associate degree | 17.6% | 35.2% | 38.5% |
| Completed bachelors | 10.8% | 27.6% | 30.3% |
| Completed masters | 2.9% | 10.4% | 11.5% |
| Completed professional degree | 0.0% | 2.8% | 3.3% |
| Completed doctorate | 0.0% | 1.2% | 1.3% |
There are a total of 5 public schools, 1 private schools and n/a post-secondary schools in St. Clair. Using the proficiency score averages, the average test scores for St. Clair, MO schools is 42%. The average student to teacher ratio is 17:1. In St. Clair, MO, an average of 77.0% of students have completed 8th grade and an average of 73.5% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Sullivan, MO | 6,672 | 63% | 31.7% |
| Union, MO | 12,241 | 49% | 3.0% |
| Washington, MO | 14,575 | 49% | 1.0% |
| Villa Ridge, MO | 3,291 | 48% | = 100 |
| Pacific, MO | 6,965 | 45% | 6.0% |
| St. Clair, MO | 4,878 | 42% | 12.2% |
| City | Population | Avg. Test Scores | National Avg. |
| Mineola, TX | 4,876 | 41% | 14.6% |
| Palos Park, IL | 4,875 | 61% | 26.6% |
| Lake Montezuma, AZ | 4,882 | 30% | 38.5% |
| Harrington Park, NJ | 4,882 | 79% | 63.5% |
| Brent, AL | 4,882 | 32% | 33.3% |
| St. Clair, MO | 4,878 | 42% | 12.2% |