Education calculators

Use your current cumulative GPA, completed credits, target GPA, planned credits, and expected future GPA to estimate how much recovery is mathematically possible.

Enter the item count, correct and incorrect group means, the total-score standard deviation, and the item value. The calculator reports difficulty, raw discrimination, corrected discrimination, and a practical review flag.

Enter variance components from a balanced G-study to project relative and absolute reliability for a planned items-by-raters design. The calculator also searches for the smallest item and rater counts that can reach your target.

Enter calibrated IRT item parameters to evaluate the probability of a correct response, the item information at a selected ability, and the ability needed to reach a target probability.

Enter item-level p × q totals and the population spread of total scores to estimate KR-20 reliability. The calculator also gives a standard error of measurement and a bounded interval around one observed score when the coefficient is valid.

Enter the number of items, mean score, and score standard deviation to estimate KR-21 reliability. The calculator also shows SEM intervals for one observed score and a Spearman-Brown estimate for reaching a target reliability.

Enter the expert-panel size and the number who rated one item essential. The calculator reports the Lawshe CVR and the exact-binomial agreement threshold for the selected significance level.

Enter a current item count and reliability estimate to predict reliability at a planned length, or to find the shortest whole-item test that reaches a target reliability.

Enter two scores on the same scale to see the observed change, the uncertainty around that change, and whether it exceeds a chosen measurement-error threshold. You can derive each SEM from reliability and score spread or enter the SEM published by the test provider.