What is the expected effect to credit of refinancing my student debt?

Question

I have $20K in student loans across 8 accounts at 3 lenders dating back from 2004-2009 here in the USA. The average interest rate is around 6%. I can likely get a fixed rate around 3.5% if I refinance, clearly an improvement. I'd love to get these rates down so I can feel like investing my disposable income is more certainly better than paying down the loans. But I'm concerned about the effect on my credit.

My credit score is currently Excellent, partially because of these loans: the average age of my credit is 10 years, and my oldest account is 16 years. Refinancing will almost certainly reduce my credit, first because of a hard credit pull (or three), but possibly more because of changes to the age of my credit. By how much should I expect my credit to be reduced, and for how long? Is there some back-of-envelope calculation for this sort of thing?

Answer 1

tl;dr; Do the refi and don't worry about your credit score.

The refi as you described can save you almost $500 in the first year, and likely thousands over the course of the loan. The slight dip to your credit score due to the hard inquiry is only temporary, and it will likely be just one instead of multiples.

Regarding the Average Age of Accounts change, there isn't much you can do about that, but my hunch is it'll hardly affect your score. Many models include the closed accounts too, and since they are all in good standing it will still help your score from the point of view of a good long term history. As anecdotal evidence, I've refinanced 2 properties multiple times in the last few years, and my credit score either didn't change, or in one case actually went up.

As a side note, temporary fluctuations in credit score do not matter in most scoring models, and should not concern you. Typically the only time your credit score matters is on the day you are applying for new credit. In the answer I linked to I mention a story about how I raised my credit score 30 points while applying for a mortgage, which was enough to get me the lowest possible interest rate.