Educational loan limits for graduate and professional students were estimated to provide manageable repayments that were a proportion of the borrowers' future consumption budget data. Based on each professional group's income profile, loan repayments were computed for each year of repayment and summed across alternative repayment periods to arrive at the aggregate ability to repay during the repayment period. Manageable aggregate ability to repay for each graduate and professional group was then converted into manageable loan principal limits for loans with alternative interest rates, amortization periods, and repayment plans (equal installment and graduate repayment option). The simulated manageable educational debt levels were intended to illustrate the relationship between the hypothetical prospective income of selected professional groups and their theoretical ability to repay educational loans. Borrowers may want to elect a graduated repayment option and to extend the repayment period from 10 to 15 years if their total educational indebtedness exceeds a threshold amount. Separate borrowing limits and graduated repayment option plans could be established under the Guaranteed Student Loan Program for borrowers in different professions. Simulated loan principal limits were run for the following groups: males with five or more years of college, law students, medical students, and doctoral scientists and engineers. Eleven tables and formulas for estimating loan repayments are included. (SW)