Hi Heather—My wife and I file our taxes jointly. We both have IBR-eligible loans. I work full-time and she stays home with our kids. As I understand it, our total IBR payment amount is based on our joint AGI and our combined student loan debt, and then that total amount is prorated between us based on our respective shares of our combined debt amount to determine our respective monthly payments, is that correct? Is that proration automatic, or is there a form we need to submit to our servicer, or some magic language we need to use, in order to request it? What I (obviously) want to avoid is a situation where we are each paying the total IBR payment based on our joint filing status, which I’ve heard is a risk of filing jointly. Your advice and expertise is much-appreciated, thank you.

You’ve got the rule right exactly. 

To notify your loan servicers, each of you should separately log into studentloans.gov with your PINs, list each other as spouses on the IBR application, and agree to use the IRS data retrieval tool to import your tax info.  But then you should still keep an eye on the process and be prepared to advocate for yourselves in writing if it isn’t handled properly the first time.