The study says the online calculators used to estimate college costs are far from accurate for students who are parents. In many cases, these federally-required calculators underestimate true costs for those students by several thousands of dollars a year per child, the report says. To adequately plan for college, student parents need accurate estimates of their total cost, including tuition and fees, room and board, books and supplies, and transportation, as well as the additional expenses related to parenting. In California, where the cost of living is high, such omissions may prevent student parents from accurately assessing the true cost of attendance, the study says. The report suggests ways to improve the estimates for this part of the population.