IIRC, the elements and their weights are published info.

If you're merely seeking info for a college prospect in your [family|circle of friends], Google would have helped, with http://www.finaid.org/calculators/finaidestimate.phtml or apps.collegeboard.com/fincalc/efc_welcome.jsp.

If, on the other hand, you need to write your own script for some reason, the paperwork seems likely to provide the elements and weights... or so I infer from this (directorym.com) instructional text:

To find out, you'll need to submit a FAFSA, the Free Application for Federal Student Aid. The Federal Student Aid program determines your financial need based on the information you provide in this form. Your income and assets, the size of your household, and if applicable, your parents' finances will determine your EFC, or Expected Family Contribution.

And if the FAFSA isn't what I suspect, I imagine you can find other sources.

Back now, to the "directorym.com" article for a few final words

There are two different formulas used to determine eligibility for financial aid. The main "Federal Methodology" applies to federal, state, and some college aid. Public universities typically use this formula. Private universities and scholarship programs use the "Institutional Methodology" (IM) to calculate eligibility for their funds.

Both formulas take into account the basics:

• income • assets • number of family members • number of family members in college

The Institutional Methodology incorporates some additional information, such as home equity and support from a non-custodial parent. It applies different formulas to some elements of your family finances, such as treatment of student assets and allowances for siblings in college. If your school asks you to submit a CSS Financial Aid profile, it will probably calculate your eligibility for its own grants based on the IM.