| Index | Portsmouth | New Hampshire | National |
| Average Test Scores | 75% | 52% | 48% |
| Student/Teacher ratio | 13:1 | 13:1 | 16:1 |
| Total public schools | 6 | 234 | 79,221 |
| Total private schools | 1 | 144 | 24,874 |
| Total post-secondary schools | 3 | 40 | 7,963 |
| Index | Portsmouth | New Hampshire | National |
| Completed 8th grade | 93.9% | 89.5% | 84.3% |
| Completed high school | 93.4% | 88.4% | 83.0% |
| Completed some college | 79.6% | 64.2% | 59.4% |
| Completed associate degree | 65.9% | 45.3% | 38.5% |
| Completed bachelors | 57.6% | 35.5% | 30.3% |
| Completed masters | 21.4% | 13.4% | 11.5% |
| Completed professional degree | 5.3% | 3.3% | 3.3% |
| Completed doctorate | 2.7% | 1.4% | 1.3% |
There are a total of 6 public schools, 1 private schools and 3 post-secondary schools in Portsmouth. Using the proficiency score averages, the average test scores for Portsmouth, NH schools is 75%. The average student to teacher ratio is 13:1. In Portsmouth, NH, an average of 93.9% of students have completed 8th grade and an average of 93.4% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Durham, NH | 12,016 | 76% | 57.8% |
| Hampton, NH | 10,002 | 70% | 45.1% |
| York Harbor, ME | 3,484 | 66% | 36.5% |
| Cape Neddick, ME | 2,563 | 65% | 34.4% |
| Kittery Point, ME | 1,034 | 65% | 34.4% |
| Portsmouth, NH | 21,418 | 75% | 55.8% |
| City | Population | Avg. Test Scores | National Avg. |
| North Bellmore, NY | 21,422 | 57% | 18.8% |
| Mukilteo, WA | 21,414 | 69% | 43.6% |
| Duarte, CA | 21,399 | 40% | 16.1% |
| Bear, DE | 21,397 | 48% | 0.7% |
| North Plainfield, NJ | 21,445 | 31% | 35.2% |
| Portsmouth, NH | 21,418 | 75% | 55.8% |
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