Saving for college is one of the biggest goals for many advisor clients, and probably the most important after saving for a house.

The costs can be almost as large and in some cases even larger. Tuition, fees and room and board average almost $21,000 at four-year public colleges for in-state students and almost $47,000 at a private nonprofit school for the 2017-2018 academic year, according to the College Board. Multiply each number by four and you get an idea of how much a college education costs based on its sticker price, assuming a student graduates in four years.

Many families won’t pay the sticker price, but how much help they will get in grants and scholarships is unknown until a students is accepted. About one in eight undergraduates will receive a private scholarship, and the average size is around $4,200 a year, says Mark Kantrowitz, publisher of savingforcollege.com.

Close to 42% who attend a private school will receive a grant, averaging $9,700 annually, and about 25% will get a state grant from a public institution averaging about $3,600. There are also federal Pell grants for those who qualify.

(Related: Top 20 Colleges Worth the Cost: Princeton Review)

Even a middle-class student attending a private school who receives an average grant and scholarship would have to come up $33,000 per year for school.

Keep in mind that the higher the income of the family and the expected family contribution (as tabulated under the Free Application for Federal Student Aid, which is required when applying for aid), the less likely they will qualify for grants or scholarships.

Given the high cost of college, many advisor clients — along with their advisors — will need to calculate how much money to save over time to help pay for college. With that in mind, we looked at many college cost calculators in order to find the best of the lot.

There are many calculators. Individual schools have them; so do financial firms like Vanguard and Fidelity, 529 savings plan funds run by financial firms or individual states and online services devoted to college financing issues.

There are two main types of college cost calculators: calculators for families who don’t have any idea which college or university their child or children will attend and calculators for those who do. The latter group can access the net price calculators that are available on the websites of individual colleges or through the U.S. Department of Education Net Price Calculator Center. All colleges and universities were directed by the Obama administration to post a net-price calculator on their websites in late October 2011. ThinkAdvisor tried out many of these calculators, all online, and here’s what we found.

General College Cost Calculators

These calculators ask a few key questions that can help families get an idea about how much they should be saving to pay for their child’s higher education.

They usually start with the cost of college. Families can input an average cost for a public institution, usually for an in-state resident, a private institution or a specific school.

Then they factor in a college cost inflation rate, the percent of costs a family plans to cover and the number of years until college. The result is the amount of money a family needs to save to pay for all or part of their child’s college education. Often the results suggest the needed additional savings via a 529 savings plan.

Many calculators also include how much money a family has already saved and expects to save on a monthly or annual basis, which provides a more complete picture about funding needs.

Calculator Assumptions

This is how many college cost calculators differentiate themselves.

College cost calculators make assumptions about the cost of college now, the annual rate of inflation in college costs and the annual return rate of returns on college savings. The calculators use default numbers that users can usually adjust.

Take the annual cost of a generic private college. The cost calculators from Vanguard, Fidelity, American Funds and the College Board all assume the costs are under $50,000 annually, when in reality many private colleges charge over $60,000. Total annual costs for New York University in the 2018-2019 academic year exceed $70,000.

A family who expects their student will attend a private institution for four years could be underestimating the cost if they use the lower cost estimates and if the student doesn’t qualify for any grants or scholarships. Families would therefore be better off entering the name of an actual college their child may attend if that’s known.

Most of these calculators assume college costs will increase 5% or 6% annually, but costs for private nonprofit and public higher-ed institutions have been rising at a rate of 3.4% annually or less since the 1987-1988 school year, according to the College Board.

The calculators also assume that savings will earn annual returns between 5% and 8% annually, which doesn’t seem like much, but consider this: Since 2000, the S&P 500 has earned an average 3.6% to 5.5% with reinvested dividends. Moreover, as the start date of college nears, it’s unlikely that families will have all of college savings invested in stocks. They will likely have pared stock portfolios and added short-term bonds or CDs, which return less than stocks, to preserve capital.

Calculators We Like

Vanguard’s college cost calculator was simple to use but comprehensive and issues a report filled with graphics illustrating how much more money a family needs to save each month to meet its college savings goal. The goal, for example, could target saving enough to fund 50% or 100% of college costs.

We also liked Bankrate.com’s calculator, which, like Vanguard’s and others, issues a report noting how much more a family needs to save per month.

Fidelity’s calculator finishes up with a report that tells you not only how far a family is from achieving its college savings goal but includes an interactive graphic that allows them to see how adjusting contributions by different amounts will get them closer to achieving their goal.

Savingforcollege.com’s calculator stands out because it’s one of the few that includes a dollar amount for scholarships and grants a student may receive and adjusts the needed family contribution accordingly. It’s not certain, however, that a student will receive the assumed amount of grants and scholarships, in which case the family could easily under-save for college.

The report also stands out for noting how a current college savings plan could affect a student’s future because it includes how much the student would have to borrow to make up the difference between the cost of the institution and their family’s contribution.

The MyinTuition Quick College Cost Estimator calculates the financing needed to attend 32 private elite U.S. colleges such as Yale, Amherst and Wellesley, where it was developed. The calculator also accounts for student scholarships and grants, which may not actually be delivered.

The questions this calculator asks, however, are different from those in other calculators. They relate to the CSS Profile questionnaire that many private colleges use when considering financial aid. Unlike the FAFSA, the CSS Profile includes home values and home equity when calculating what families can afford to pay for college. On the plus side, the annual sticker costs are accurate because the calculator uses the total costs from participating institutions, usually ranging near $70,000 per year.

Calculators We Didn’t Like

Sallie Mae, once a government entity that serviced federal student loans and now a provider of private student loans, has one of the worst student loan calculators because it oversimplifies. All it asks is the cost of college per year — without providing any numbers to input — the number of years until college and the number of years in college. That’s it. It doesn’t  include the amount of money already saved or a return rate showing how much savings will grow over time. Sallie Mae does have a more extensive tool called a College Planning Calculator but you’ll have to search for it under Tools in the College Planning section of its website.

The College Board’s College Cost Calculator is also disappointing because nowhere does it ask how much money a family has already saved for retirement or calculate how much a family would need to save per month or year to have enough to meet their college savings goals. It only offers the total costs and total savings goal based on the percentage a family is willing to pay. In other words, it doesn’t provide any information a family doesn’t already know, assuming they know the average cost of four years at a public or private college and how much of that they want to pay for.

Individual College Cost Calculators

These calculators also vary but some use the same engine. For example, Syracuse, University of North Carolina at Chapel Hill, Northwestern University, Boston College and Boston University (and no doubt many others) use a calculator powered by the College Board, Rewire Technology Inc.

This particular calculator states that the process is not an application for student aid, the parameters are based on freshmen and the net price is dependent on the accuracy and completeness of information provided. It also notes that the net price is only an approximation on what you will be expected to contribute.

In our assessment, ThinkAdvisor looked at student calculators for both state and private universities and colleges, and, for the state schools, the calculations for in-state residents and out-of-state residents. We used a “virtual” family and student: dual income parents earning between $105,000 and $125,000, two kids in college and a student with an ACT of 27 and SAT of 1430.

We were surprised to find that private schools at this level were more generous with aid, grants and work-study than many public institutions. For example, both Princeton University and Northwestern University were generous with aid.

(Related: Top 10 Colleges With Best Financial Aid Packages: Princeton Review)

The total cost for Northwestern is about $75,700 per year, but with gift/aid scholarship of $59,765, and self-help of $2,700, the cost dropped down to $13,233 per year. Princeton was even more generous, with costs coming down to $1,800 a year. Of course, a student would have to be accepted, and again, our “virtual” dual income is relatively low compared to the income of the clients that many of our readers serve.

State schools for in-state and out-of-state students were not very generous as a rule. The University of North Carolina at Chapel Hill was an exception. With some grants and aid, the cost for out-of-state residents fell to between $3,364 and $15,000 per year, a steal compared to University of Wisconsin-Madison at $45,000 from out of state, even with some assistance.

Even one of the most coveted public schools in the country, the University of California, Los Angeles, seems to provide aid, bringing down in-state costs to $16,000 a year, according to a very simple calculator whose accuracy may be questionable. The rub here, of course, is getting into the school.

UW-Madison’s calculator was very thorough for both in- and out-of-state students, providing a grid of costs even before needing to use the calculator.

The University of Texas at Austin didn’t give much in the way of financial aid but compared well in price ($42,000 a year) to local schools such as Southern Methodist University ($52,000) and Texas A&M ($56,000).

The best advice for parents and children is to have your documents handy, including parental income, savings, tax returns, investments, student work income and savings and ACT/SAT scores when you start this process.

Many of these calculators are very simple and won’t ask for this information, but for those that do, having the information on hand can help you get a more accurate view of what will be your out-of-pocket cost.

Parents also have another option: Collegebacker.com and other firms that have set up crowdfunding for families to raise money for college.

Collegebacker.com is a new 529 savings program that is very low in fees and has a program that parents can set up to crowdfund for college savings. We’re not talking about the general public, but a program that allows relatives and friends to formally give to a savings program for the child’s college.

Better than savings bonds, this program was developed with millennials in mind who “are comfortable to talk about financials and to put up crowdfunding links,” says co-founder Abby Chao. The site even has its own calculator that asks the child’s age and what type of school they (parents) want them to go to (private, in-state/out-of-state) and it will generate a rough idea of the amount that parents need to raise.

— Related on ThinkAdvisor:

• Top 10 Best Colleges With Low Student Debt: Kiplinger
• 15 Lowest Cost 529 College Savings Plans