I rarely get this excited about student loan repayment tools. First, let's face it, they aren't that exciting. Second, most of them have an obvious flaw or area where they break down. If there is a point where the VIN Foundation Student Debt Center's loan repayment simulator breaks down, I wasn't able to find it.
And from there, it tackles all the basics (income, raises, family size), and then some. The second part that VIN nails is the family information. I've never seen a student loan calculator with this many options in the family section. It gets all the low hanging fruit, like spouse's loan balance and interest rate, but also includes the often forgotten pieces, like tax filing status (important for income-driven repayments), and spouse's repayment plan (almost never included in other calculators). Not only that, the calculator from the VIN Foundation allows you to estimate what years your future children will be born! Such an obvious oversight that isn't included in any other calculators. While not the most important component, it does definitely play into your taxable income, which is crucial on an income-driven repayment plan.
The cherry on top is the advanced settings, which even lets you estimate the future tax rate that you would pay on your student loan balance. Yes it's easy to calculate on your own, but they leave no stone unturned with this calculator.
The only critiques of this calculator are the output. They do a great job breaking down the different repayment options, but the graphics leave something do be desired. The total loan balance graphic is somewhat confusing and not easy to navigate, but the monthly repayment summary graphic is nice. Overall, the VIN Foundation's Student Debt Center Student Loan Repayment Simulator is the best on the internet, and the one I'll be using from here on.