| Index | Custer | Washington | National |
| Average Test Scores | 50% | 54% | 48% |
| Student/Teacher ratio | n/a | 20:1 | 16:1 |
| Total public schools | n/a | 1,991 | 79,221 |
| Total private schools | n/a | 548 | 24,874 |
| Total post-secondary schools | n/a | 147 | 7,963 |

| Index | Custer | Washington | National |
| Completed 8th grade | 80.6% | 87.5% | 84.3% |
| Completed high school | 80.6% | 86.6% | 83.0% |
| Completed some college | 35.1% | 67.7% | 59.4% |
| Completed associate degree | 0.0% | 43.3% | 38.5% |
| Completed bachelors | 0.0% | 33.6% | 30.3% |
| Completed masters | 0.0% | 12.3% | 11.5% |
| Completed professional degree | 0.0% | 3.6% | 3.3% |
| Completed doctorate | 0.0% | 1.5% | 1.3% |
There are a total of n/a public schools, n/a private schools and n/a post-secondary schools in Custer. Using the proficiency score averages, the average test scores for Custer, WA schools is 50%. The average student to teacher ratio is n/a. In Custer, WA, an average of 80.6% of students have completed 8th grade and an average of 80.6% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Everson, WA | 2,830 | 58% | 21.5% |
| Lynden, WA | 15,226 | 53% | 11.0% |
| Ferndale, WA | 15,070 | 52% | 7.3% |
| Bellingham, WA | 92,702 | 51% | 5.4% |
| Blaine, WA | 5,592 | 49% | 2.3% |
| Custer, WA | 304 | 50% | 3.1% |
| City | Population | Avg. Test Scores | National Avg. |
| Hannibal, OH | 304 | 48% | 1.0% |
| Hiddenite, NC | 304 | 38% | 21.9% |
| Dodson, LA | 304 | 67% | 39.6% |
| Goose Lake, IA | 304 | 77% | 60.9% |
| Morganton, GA | 304 | 40% | 17.7% |
| Custer, WA | 304 | 50% | 3.1% |